Drought Responses on Physiological Attributes of *Zea mays* in Relation to Nitrogen and Source-Sink Relationships

*Suphia Rafique*

## **Abstract**

Maize is the staple food crop and essential for world food security. Maize plants' water requirement is high for proper growth and development at vegetative stage and grain formation at reproductive stage. Drought is the major abiotic stress that affects almost all the growth stages of maize crop and it has a strong impact on all the physiological process of maize plants. Similarly, N metabolism is of central importance during drought stress. Nitrogen (N) is one of the macronutrients; it is a major requirement for crop growth and grain yield of maize. Therefore, nitrogen and water separately or in combination are the two most critical factors in maize production. Drought modifies source-sink relations and weakens the source and sink strength, which disturbs plant's growth, plant's adaptation to stress, and consequently affects crop productivity.

**Keywords:** maize, drought, nitrogen, source-sink relationship

#### **1. Introduction**

Plants are nonmotile, and they protect themselves from various biotic and abiotic stresses through structural and metabolic changes like altering leaf orientation, transpirational cooling, or adjustment of membrane lipid compositions [1]. Maize is a staple food crop that grows under optimal environmental conditions and throughout their life span is often exposed to various abiotic stresses [2] like either combined stresses like drought and heat, drought and salinity, drought and low-N stresses, or singly drought. In combined stress, plants show a wide range of responses that brings changes in growth and morphology, and the plants' ability to withstand these stresses greatly varies from species to species [3]. However, drought along with high frequencies, longer durations, and large ranges occur almost yearly across the globe, even in wet and humid regions [4, 5]. Water deficit is the most detrimental environmental stress that adversely affects the maize productivity. The effect of drought is manifested at cellular, physiological biochemical, metabolic, proteins, and gene levels. Water is an essential component for plants; it maintains cell turgidity and keeps the structure intact (by keeping the pressure inside cells high) so that they are fully expanded (i.e., turgid). In wilted plants, when turgor pressure approaches to zero, the cell membranes collapses, damage and becomes

leaky, the key enzymes proteins denatured and their structure altered. To ensure high survival rates and production under drought conditions, maize plants rely on several strategies, including drought avoidance, escape, and tolerance [6–8]. Nitrogen plays a major role in plant nutrition and also combats with several abiotic stresses like salinity, drought, heat stress, etc. [9–13], but this mineral element is most often deficient in arable soils. Though the requirement of nitrogen is greatest among all mineral elements, its deficiency limits the plant's growth and development [14–16]. There is a tight regulation of carbon and nitrogen metabolism in photosynthesis and N uptake [14, 17–19]. In a review, Aziz Khan et al. [20] outline the nitrogen (N) responses in crop production and to ameliorate abiotic stresses for better crop production. Further they emphasize that nitrate and ammonium nitrogen are essential nutrients for successful crop production [21]. Moreover, shortage and N excess affect assimilate partitioning between vegetative and reproductive organs [22]. Mineral nutrition influences the physiological response of plants to water stress [23]. While Waraich et al. [24] discussed the role of macro- and micronutrients to decrease the adverse effect of drought in crop plants. Therefore, water and nitrogen affects the crop growth, development, and production either separately or in combination. Humbert et al. [25] observed the physio-molecular changes in response to water and nitrogen and finally concluded that the responses of plants to the combination of these two stresses may cause additional effect that was different from the individual effects, and hence, cannot be inferred from the end results obtained from different stresses applied individually. Drought affects maize grain yield to some degree at almost all growth stages, but the crop is the most susceptible during flowering [26, 27]. At the reproductive phase, N availability affects assimilate partitioning between vegetative and reproductive organs and N metabolism in young ear shoots [28]. Therefore, the timing and intensity of stress determine the extent to limits yield either due to source or sink limitations.

#### **2. Maize response under drought stress**

#### **2.1 Effect of drought on morpho-physiological parameters**

The water deficit conditions Boyer [29] showed the decrease in leaf area attributed to decrease rate leaf initiation and expansion or increase leaf senescence or shedding. Though the number of leaves per plant did not reduce in early vegetative maize growth in severe nonlethal water deficit conditions, Abrecht and Carberry [30] also demonstrated the gradual reduction in plant height in maize with increasing water deficit. Further supported by Moss and Downey [31] showed the significant reduction in plant height with increase in water stress. While, dry matter yield accumulation depends on the leaf area and leaf dry weight because leaf area is the major assimilatory surface for most crop any factor that affects the leaf area also affects dry matter [32]. In similar way, the short term responses of corn to a pre-anthesis water deficit, delayed leaf tip emergence and reduction in leaf area. While long-term consequences of water deficits have reduced final sizes of the leaves and internodes [33]. Drought stress significantly repressed relative leaf water content, leaf size, and photosynthesis-related parameters in maize seedling [34]. Drought affects various morpho-physiological processes including plant biomass, root length, shoot length, photosynthesis, water use efficiency (WUE) and leaf water content [35, 36]. At early growth stage 50 maize genotypes for drought tolerance was assessed. Principal component analysis revealed important morpho-physiological traits (FSL, FRL, DSW, DRW, RWC, and TDM) plays key role in drought tolerance. Later, Ali et al. [37] identified various

**447**

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

stages reduced plant height, as well as leaf area development [39].

morpho-physiological traits that have higher heritability, genetic advancement, and correlation and which contribute for improved maize grain yield. A set of 24 genotypes bred at different centers in India as well as in CIMMYT showing variability for drought tolerance were selected for molecular and morpho-physiological characterization. Phenotyping of inbred by morpho-physiological traits revealed that there was a positive relationship among root length, chlorophyll content, relative water content while anthesis-silking interval (ASI) have negative relationship with all these traits [38]. Water stress occurring during vegetative and tasseling

In a study Anjum et al. [40] showed that drought stress in maize led to considerable decline in net photosynthesis (33.22%), transpiration rate (37.84%), stomatal conductance (25.54%), water use efficiency (50.87%), intrinsic water use efficiency (11.58%) and intercellular CO2 (5.86%) as compared to well water (WW) control. The main cause of reduced photosynthesis under drought stress is due to decreases in both assimilation (A) and internal CO2 concentration, that finally inhibits total photosynthetic metabolism [41]. Besides there are other several non-stomatal effects during drought which are responsible for stomatal closure. These include photophosphorylation, ribulose-1,5-bisphosphate (RuBP) regeneration [42, 43], rubisco activity, and ATP synthesis [44, 45]. The response of growth and some physiological characteristics were compared in two maize *(Zea mays* L.) cultivars, one drought-resistant (PNR473) and the other drought-sensitive (SR52). Droughtresistant (PNR473) had a higher growth rate and deeper rooting than the droughtsensitive cultivar under water stress treatment. But the drought-resistant cultivar had a higher transpiration rate and lower diffusive resistance during the onset of water stress, and higher relative water content and levels of abscisic acid and proline throughout the period of water stress [46]. While, Jama and Ottaman [47] reported delay in the irrigation during early growth stages of a corn plant (including anthesis) decreased plant dry weight. The responses of maize (*Zea mays* L.) from the third leaf stage to maturity for different soil water levels (well watered, moderately stressed, and severely stressed) indicated that drought stress relied on drought intensity and duration, with more severe drought stress creating more serious effects on maize. It is well known that leaf water status always interacts with stomatal conductance through plant hormone abscisic acid, increased production of ABA would help the plants to survive under drought stress [48]. According to Bray [49], dry soil induced and increased ABA concentrations in the roots to maintain root growth, increase root hydraulic conductivity, through these process shoot water uptake increases thus drought induced root-to-leaf signaling. Also direct correlation between the xylem ABA content and stomatal conductance has been demonstrated [50]. The role of other phytohormones like Brassinosteroid is for plant growth, as they are involved in main plant antioxidant processes encompassing the regulation and enhancement of plant tolerance against different environmental stresses [51].

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

**2.2 Photosynthesis under drought stress**

**2.3 Metabolic changes under drought stress**

To maintain cell turgor and to lower the osmotic potential plants accumulate

metabolites, such as sugars and amino acids, have also been reported to accumulate during water stress [53]. Two maize (*Zea mays* L*.*) cultivars, 704 and 301, accumulate soluble sugars, starch, and proline content in shoots and roots in response to drought stress. This suggests role of sugars in osmotic adjustment whereas, proline

different types of organic and inorganic solutes in the cytosol [52]. Primary

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

morpho-physiological traits that have higher heritability, genetic advancement, and correlation and which contribute for improved maize grain yield. A set of 24 genotypes bred at different centers in India as well as in CIMMYT showing variability for drought tolerance were selected for molecular and morpho-physiological characterization. Phenotyping of inbred by morpho-physiological traits revealed that there was a positive relationship among root length, chlorophyll content, relative water content while anthesis-silking interval (ASI) have negative relationship with all these traits [38]. Water stress occurring during vegetative and tasseling stages reduced plant height, as well as leaf area development [39].

#### **2.2 Photosynthesis under drought stress**

*Abiotic Stress in Plants*

**2. Maize response under drought stress**

**2.1 Effect of drought on morpho-physiological parameters**

The water deficit conditions Boyer [29] showed the decrease in leaf area attributed to decrease rate leaf initiation and expansion or increase leaf senescence or shedding. Though the number of leaves per plant did not reduce in early vegetative maize growth in severe nonlethal water deficit conditions, Abrecht and Carberry [30] also demonstrated the gradual reduction in plant height in maize with increasing water deficit. Further supported by Moss and Downey [31] showed the significant reduction in plant height with increase in water stress. While, dry matter yield accumulation depends on the leaf area and leaf dry weight because leaf area is the major assimilatory surface for most crop any factor that affects the leaf area also affects dry matter [32]. In similar way, the short term responses of corn to a pre-anthesis water deficit, delayed leaf tip emergence and reduction in leaf area. While long-term consequences of water deficits have reduced final sizes of the leaves and internodes [33]. Drought stress significantly repressed relative leaf water content, leaf size, and photosynthesis-related parameters in maize seedling [34]. Drought affects various morpho-physiological processes including plant biomass, root length, shoot length, photosynthesis, water use efficiency (WUE) and leaf water content [35, 36]. At early growth stage 50 maize genotypes for drought tolerance was assessed. Principal component analysis revealed important morpho-physiological traits (FSL, FRL, DSW, DRW, RWC, and TDM) plays key role in drought tolerance. Later, Ali et al. [37] identified various

leaky, the key enzymes proteins denatured and their structure altered. To ensure high survival rates and production under drought conditions, maize plants rely on several strategies, including drought avoidance, escape, and tolerance [6–8]. Nitrogen plays a major role in plant nutrition and also combats with several abiotic stresses like salinity, drought, heat stress, etc. [9–13], but this mineral element is most often deficient in arable soils. Though the requirement of nitrogen is greatest among all mineral elements, its deficiency limits the plant's growth and development [14–16]. There is a tight regulation of carbon and nitrogen metabolism in photosynthesis and N uptake [14, 17–19]. In a review, Aziz Khan et al. [20] outline the nitrogen (N) responses in crop production and to ameliorate abiotic stresses for better crop production. Further they emphasize that nitrate and ammonium nitrogen are essential nutrients for successful crop production [21]. Moreover, shortage and N excess affect assimilate partitioning between vegetative and reproductive organs [22]. Mineral nutrition influences the physiological response of plants to water stress [23]. While Waraich et al. [24] discussed the role of macro- and micronutrients to decrease the adverse effect of drought in crop plants. Therefore, water and nitrogen affects the crop growth, development, and production either separately or in combination. Humbert et al. [25] observed the physio-molecular changes in response to water and nitrogen and finally concluded that the responses of plants to the combination of these two stresses may cause additional effect that was different from the individual effects, and hence, cannot be inferred from the end results obtained from different stresses applied individually. Drought affects maize grain yield to some degree at almost all growth stages, but the crop is the most susceptible during flowering [26, 27]. At the reproductive phase, N availability affects assimilate partitioning between vegetative and reproductive organs and N metabolism in young ear shoots [28]. Therefore, the timing and intensity of stress determine the extent to limits yield either due to source or sink limitations.

**446**

In a study Anjum et al. [40] showed that drought stress in maize led to considerable decline in net photosynthesis (33.22%), transpiration rate (37.84%), stomatal conductance (25.54%), water use efficiency (50.87%), intrinsic water use efficiency (11.58%) and intercellular CO2 (5.86%) as compared to well water (WW) control. The main cause of reduced photosynthesis under drought stress is due to decreases in both assimilation (A) and internal CO2 concentration, that finally inhibits total photosynthetic metabolism [41]. Besides there are other several non-stomatal effects during drought which are responsible for stomatal closure. These include photophosphorylation, ribulose-1,5-bisphosphate (RuBP) regeneration [42, 43], rubisco activity, and ATP synthesis [44, 45]. The response of growth and some physiological characteristics were compared in two maize *(Zea mays* L.) cultivars, one drought-resistant (PNR473) and the other drought-sensitive (SR52). Droughtresistant (PNR473) had a higher growth rate and deeper rooting than the droughtsensitive cultivar under water stress treatment. But the drought-resistant cultivar had a higher transpiration rate and lower diffusive resistance during the onset of water stress, and higher relative water content and levels of abscisic acid and proline throughout the period of water stress [46]. While, Jama and Ottaman [47] reported delay in the irrigation during early growth stages of a corn plant (including anthesis) decreased plant dry weight. The responses of maize (*Zea mays* L.) from the third leaf stage to maturity for different soil water levels (well watered, moderately stressed, and severely stressed) indicated that drought stress relied on drought intensity and duration, with more severe drought stress creating more serious effects on maize. It is well known that leaf water status always interacts with stomatal conductance through plant hormone abscisic acid, increased production of ABA would help the plants to survive under drought stress [48]. According to Bray [49], dry soil induced and increased ABA concentrations in the roots to maintain root growth, increase root hydraulic conductivity, through these process shoot water uptake increases thus drought induced root-to-leaf signaling. Also direct correlation between the xylem ABA content and stomatal conductance has been demonstrated [50]. The role of other phytohormones like Brassinosteroid is for plant growth, as they are involved in main plant antioxidant processes encompassing the regulation and enhancement of plant tolerance against different environmental stresses [51].

#### **2.3 Metabolic changes under drought stress**

To maintain cell turgor and to lower the osmotic potential plants accumulate different types of organic and inorganic solutes in the cytosol [52]. Primary metabolites, such as sugars and amino acids, have also been reported to accumulate during water stress [53]. Two maize (*Zea mays* L*.*) cultivars, 704 and 301, accumulate soluble sugars, starch, and proline content in shoots and roots in response to drought stress. This suggests role of sugars in osmotic adjustment whereas, proline

minimized the damage caused by dehydration [54]. The high salt concentration of soil causes a water deficit in crops [55], exogenous application of SA mitigated the adverse effects of salinity on maize plants by osmoregulation which is possibly mediated by increased production of sugar as well as proline [9]. Besides, the ROS (including oxygen ions, free radicals, and peroxidases) forms major by-product of normal metabolism and in abiotic stress conditions. However, during environmental stress such as drought, ROS levels increase dramatically resulting in oxidative damage to proteins, DNA, and lipids [56]. Among six maize genotypes (A638, B73, Grace-E5, Lo964, Lo1016, and Va35) studied, the drought-sensitive maize genotypes accumulated significantly more reactive oxygen species (ROS) and reactive nitrogen species (RNS). In addition, they showed rapid increases in enzyme activities involved in ROS and RNS metabolism compared to tolerant genotypes. However, antioxidant enzyme activities were higher of tolerant genotypes than in the sensitive genotypes [57]. In a study, the protective role of biochar (date and wheat) in combination with Me and P against water stress in two maize varieties were examined. The maize variety Mallika performed better and was more drought-tolerant with its increased osmolyte production and an efficient antioxidant defense system that eliminated ROS. Hence, ROS elimination further alleviated the damage to the photosynthesis system induced by water stress. On other hand, Azam variety was more sensitivity to drought [58]. Plants tolerate the water deficit conditions by adjusting their physiological and biochemical approaches. Maize leaves subjected to water deficit rigorously down-regulated NR activity and photosynthesis, also a correlation between maximal extractable foliar nitrate reductase (NR) activity and the rate of CO2 assimilation was observed [59]. The assimilatory sulfate reduction in roots and leaves of the staple crop maize demonstrated the organ specific impact of drought upon sulfate metabolism. Under drought stress, the allocation of sulfate was significantly shifted to the roots allowed for significant increase of thiols derived from sulfate assimilation in roots. This enabled roots to produce biomass, while leaf growth was stopped. Therefore, sulfur metabolism related alterations at the transcriptional, metabolic and enzyme activity level are consistent with a promotion of root growth to search for water at the expense of leaf growth. The results provide evidence for the importance of antagonistic regulation of sulfur metabolism in leaves and roots to enable successful drought stress response at the whole plant level [60]. During the silking and blister stages moderate stress significantly change the relative water content (RWC) and also change the relative conductivity (RC) *(P* < 0.05) of the leaves; however, severe stress significantly decrease *(P* < 0.01) the leaf RWC and increase *(P* < 0.01) membrane permeability (leaf relative conductivity). Furthermore, under severe drought stress antioxidant enzyme activities declined *(P* < 0.01) in later stages, namely for superoxide dismutase (SOD) the tasseling and blister stages, for peroxidase (POD) the milk stage, and for catalase (CAT) during the tasseling, blister, and milk stages. Meanwhile, membrane lipid peroxidation (measured as malondialdehyde content) significantly increased *(P* < 0.01) in all stages [61].

#### **2.4 Drought-tolerance mechanism**

Phytohormones like, ABA, IAA, CKs, GA, SA, BRs, JA, ethylene, and triazole are directly or indirectly involved in plant responses to a wide range of stresses. They play critical roles in regulating plant growth and development, and stress tolerance to promote survival and acclimatize to varying environments [10]. Abscisic acid accumulates in response to drought stress and displays its well characterized effect on stomatal closure and promotes root growth in maize

**449**

adaptive genotypes.

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

higher chlorophyll content (*r* = 0.874∗∗∗) and Fv/Fm (*r* = 0.626<sup>∗</sup>

drought recovery. In addition, leaf water potential, chlorophyll content, and Fv/ Fm could be used as efficient reference indicators in the selection of drought-

) contributes to

seedlings at low water potential [62]. Another possible role of endogenous ABA is to modulate glycinebetaine (GB) metabolism in maize particularly at the seedling stage in drought stress. The leaves of two maize cultivars, Zhengdan 958 (ZD958; drought-tolerant), and Jundan 20 (JD20; drought-sensitive) after exposure to integrated root-zone drought stress (IR-DS) shows increased betaine aldehyde dehydrogenase (BADH) activity and choline content the key enzyme and initial substrate, in GB biosynthesis. The peak of ABA content reached earlier than that of GB in the leaves of drought-stressed maize plants. Therefore, endogenous ABA seemed to be involved in modulating GB accumulation by enhancing BADH activity, thereby improving leaf RWC and enhancing shoot DM in droughtstressed maize plants, especially in the drought-sensitive cultivar (JD20) [63]. Similarly, Si application (400 mg L−1) had positive effect on photosynthesis, water use efficiency, stomatal conductance, cholorophyll contents, Rubisco activity, and Rubisco activation state at 20 days of drought. Possibly Si may have direct or indirect role in maintenance of more active Rubisco enzyme and Rubisco activase and more stable proteins for carbon assimilation under stress conditions [64]. Maize was subjected to drought at the start of tasseling (6 days) followed by foliar spray of BR (0.1 mg l). Exogenous application of BR remarkably improved the gas exchange attributes, plant height, leaf area, cobs per plant, seedling dry weight both under drought and well-watered conditions [40]. The formation of cortical aerenchyma (RCA) in maize roots is associated with drought tolerance. RCA reduces root respiration by converting living cortical tissue to air volume. It has been hypothesized that RCA or large cortical cell size (CCS) increases drought tolerance by reducing root metabolic costs, permitting greater root growth and water acquisition from drying soil [65, 66]. Maize growth and yield responses were related to ROS production, osmolyte accumulation, and activation of anti-oxidative defense system under drought conditions. The regulation of these physio-biochemical responses of plants can be used as markers for drought stress tolerance [67]. Drought-tolerance mechanism is difficult in maize this may be due to complex genetic makeup. Metabolic traits provides better substitute to unravel the genetic mechanism of drought tolerance. The physiological status of plants can be monitored by metabolites that interconnect the visible phenotype with core genome, so that gene or gene loci could be identified and selected which are less affected by environmental factors [68–71]. However, the negative effects of abiotic stresses can be minimized by adopting the genetic approaches or by inducing resistance through transgenic approaches [3]. The importance of QTLs-based approach is associated to improve the maize crop performance under various abiotic stresses and in achieving increase in maize yield. Besides, QTLs with large effect and linked with stress-tolerance traits provides several modes to investigate the various components affecting source sink relationships of maize plants under abiotic stress [72]. Chen et al. [73] compares the role of drought resistance and drought recovery in drought adaptation in maize seedlings. After recovery most of the physiological parameters (like leaf water content, water potential, osmotic potential, gas exchange parameters, chlorophyll content, Fv/Fm and nitrogen content, and increased H2O2 accumulation and lipid peroxidation) rapidly return to normal level. Correlation analysis shows that physiological bases of drought adaptability closely related to drought recovery (*r* = 0.332) and not to drought resistance and (*r* = 0.714∗∗) both are definitely different. Under drought stress

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

#### *Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

seedlings at low water potential [62]. Another possible role of endogenous ABA is to modulate glycinebetaine (GB) metabolism in maize particularly at the seedling stage in drought stress. The leaves of two maize cultivars, Zhengdan 958 (ZD958; drought-tolerant), and Jundan 20 (JD20; drought-sensitive) after exposure to integrated root-zone drought stress (IR-DS) shows increased betaine aldehyde dehydrogenase (BADH) activity and choline content the key enzyme and initial substrate, in GB biosynthesis. The peak of ABA content reached earlier than that of GB in the leaves of drought-stressed maize plants. Therefore, endogenous ABA seemed to be involved in modulating GB accumulation by enhancing BADH activity, thereby improving leaf RWC and enhancing shoot DM in droughtstressed maize plants, especially in the drought-sensitive cultivar (JD20) [63]. Similarly, Si application (400 mg L−1) had positive effect on photosynthesis, water use efficiency, stomatal conductance, cholorophyll contents, Rubisco activity, and Rubisco activation state at 20 days of drought. Possibly Si may have direct or indirect role in maintenance of more active Rubisco enzyme and Rubisco activase and more stable proteins for carbon assimilation under stress conditions [64]. Maize was subjected to drought at the start of tasseling (6 days) followed by foliar spray of BR (0.1 mg l). Exogenous application of BR remarkably improved the gas exchange attributes, plant height, leaf area, cobs per plant, seedling dry weight both under drought and well-watered conditions [40]. The formation of cortical aerenchyma (RCA) in maize roots is associated with drought tolerance. RCA reduces root respiration by converting living cortical tissue to air volume. It has been hypothesized that RCA or large cortical cell size (CCS) increases drought tolerance by reducing root metabolic costs, permitting greater root growth and water acquisition from drying soil [65, 66]. Maize growth and yield responses were related to ROS production, osmolyte accumulation, and activation of anti-oxidative defense system under drought conditions. The regulation of these physio-biochemical responses of plants can be used as markers for drought stress tolerance [67]. Drought-tolerance mechanism is difficult in maize this may be due to complex genetic makeup. Metabolic traits provides better substitute to unravel the genetic mechanism of drought tolerance. The physiological status of plants can be monitored by metabolites that interconnect the visible phenotype with core genome, so that gene or gene loci could be identified and selected which are less affected by environmental factors [68–71]. However, the negative effects of abiotic stresses can be minimized by adopting the genetic approaches or by inducing resistance through transgenic approaches [3]. The importance of QTLs-based approach is associated to improve the maize crop performance under various abiotic stresses and in achieving increase in maize yield. Besides, QTLs with large effect and linked with stress-tolerance traits provides several modes to investigate the various components affecting source sink relationships of maize plants under abiotic stress [72]. Chen et al. [73] compares the role of drought resistance and drought recovery in drought adaptation in maize seedlings. After recovery most of the physiological parameters (like leaf water content, water potential, osmotic potential, gas exchange parameters, chlorophyll content, Fv/Fm and nitrogen content, and increased H2O2 accumulation and lipid peroxidation) rapidly return to normal level. Correlation analysis shows that physiological bases of drought adaptability closely related to drought recovery (*r* = 0.332) and not to drought resistance and (*r* = 0.714∗∗) both are definitely different. Under drought stress higher chlorophyll content (*r* = 0.874∗∗∗) and Fv/Fm (*r* = 0.626<sup>∗</sup> ) contributes to drought recovery. In addition, leaf water potential, chlorophyll content, and Fv/ Fm could be used as efficient reference indicators in the selection of droughtadaptive genotypes.

*Abiotic Stress in Plants*

minimized the damage caused by dehydration [54]. The high salt concentration of soil causes a water deficit in crops [55], exogenous application of SA mitigated the adverse effects of salinity on maize plants by osmoregulation which is possibly mediated by increased production of sugar as well as proline [9]. Besides, the ROS (including oxygen ions, free radicals, and peroxidases) forms major by-product of normal metabolism and in abiotic stress conditions. However, during environmental stress such as drought, ROS levels increase dramatically resulting in oxidative damage to proteins, DNA, and lipids [56]. Among six maize genotypes (A638, B73, Grace-E5, Lo964, Lo1016, and Va35) studied, the drought-sensitive maize genotypes accumulated significantly more reactive oxygen species (ROS) and reactive nitrogen species (RNS). In addition, they showed rapid increases in enzyme activities involved in ROS and RNS metabolism compared to tolerant genotypes. However, antioxidant enzyme activities were higher of tolerant genotypes than in the sensitive genotypes [57]. In a study, the protective role of biochar (date and wheat) in combination with Me and P against water stress in two maize varieties were examined. The maize variety Mallika performed better and was more drought-tolerant with its increased osmolyte production and an efficient antioxidant defense system that eliminated ROS. Hence, ROS elimination further alleviated the damage to the photosynthesis system induced by water stress. On other hand, Azam variety was more sensitivity to drought [58]. Plants tolerate the water deficit conditions by adjusting their physiological and biochemical approaches. Maize leaves subjected to water deficit rigorously down-regulated NR activity and photosynthesis, also a correlation between maximal extractable foliar nitrate reductase (NR) activity and the rate of CO2 assimilation was observed [59]. The assimilatory sulfate reduction in roots and leaves of the staple crop maize demonstrated the organ specific impact of drought upon sulfate metabolism. Under drought stress, the allocation of sulfate was significantly shifted to the roots allowed for significant increase of thiols derived from sulfate assimilation in roots. This enabled roots to produce biomass, while leaf growth was stopped. Therefore, sulfur metabolism related alterations at the transcriptional, metabolic and enzyme activity level are consistent with a promotion of root growth to search for water at the expense of leaf growth. The results provide evidence for the importance of antagonistic regulation of sulfur metabolism in leaves and roots to enable successful drought stress response at the whole plant level [60]. During the silking and blister stages moderate stress significantly change the relative water content (RWC) and also change the relative conductivity (RC) *(P* < 0.05) of the leaves; however, severe stress significantly decrease *(P* < 0.01) the leaf RWC and increase *(P* < 0.01) membrane permeability (leaf relative conductivity). Furthermore, under severe drought stress antioxidant enzyme activities declined *(P* < 0.01) in later stages, namely for superoxide dismutase (SOD) the tasseling and blister stages, for peroxidase (POD) the milk stage, and for catalase (CAT) during the tasseling, blister, and milk stages. Meanwhile, membrane lipid peroxidation (measured as malondialdehyde content) significantly

**448**

increased *(P* < 0.01) in all stages [61].

**2.4 Drought-tolerance mechanism**

Phytohormones like, ABA, IAA, CKs, GA, SA, BRs, JA, ethylene, and triazole are directly or indirectly involved in plant responses to a wide range of stresses. They play critical roles in regulating plant growth and development, and stress tolerance to promote survival and acclimatize to varying environments [10]. Abscisic acid accumulates in response to drought stress and displays its well characterized effect on stomatal closure and promotes root growth in maize

#### **3. Nutrient status in drought**

The role of N metabolism regulation in maize drought tolerance was comprehensively studied [74]. Drought have strong impact on all the physiological process of plants and N metabolism is of central importance during drought stress because to survive drought and to maintain growth plants adaptive strategies includes such as improved nutrient uptake and transport, photosynthesis regulation, and to produced solutes and proteins that contains N compounds such as amino acids, amides and betaines. While Kant et al. [75] reported that relationship between drought and N nutrition consists of a complex network of regulatory interactions that affects almost all physiological processes in plants. Nitrogen (N) is one of the macronutrients, its major requirement for crop growth and grain yield of maize, whereas maize water requirement is highest in the reproductive stage [76]. Therefore, nitrogen and water separately or in combination are two are most critical factors in maize production. According to Saud et al. [77] the use of nutritional soil with a proper nitrogen rate remained effective in ameliorating the adverse influence of drought stress. However, a contrast study showed low field capacity irrigation and low nitrogen fertilizer rates application improves water use efficiency and nitrogen recovery efficiency (NRE) simultaneously [78]. Water and nutrient availability influence root system architecture and development [79, 80]. During vegetative stages of corn, under moderate drought stress rooting depth typically increases, allowing more efficient uptake of water and nutrients from deeper within the soil profile [81]. The increase in plant height related with increasing N fertilizer application under drought stress [82, 83]. Andrade [84] reported that N deprivation reduced leaf area index, leaf area duration, radiation interception, and radiation use efficiency. Improved tolerance to various abiotic stresses alternative breeding strategies are adopted, one of them is to select and inbreed maize plants under high population density to improved tolerance for low-N and drought [85]. Although under dense plant population maize prone to lodging due to increase in plant height and reduced culum diameters makes the stem weaker [86]. The mechanism underlying tolerance to high population density and low-N diverse tropical germplasm were grown under optimal, high plant population density and low-N. The association between ASI and grain yield, delayed senescence (expressed as chlorophyll concentration or number of green leaves above the ear) and ear/tassel weight ratio was observed in low-N. Also, grain yield negatively correlated with abortion rate. While under optimal and high population density, a positive association was reported between ovule number and abortion rate, suggesting a source limitation for C products [87]. In the same way selection of hybrid progenies for mid-season drought tolerance was due to improvements in morpho-physiological secondary traits such as reduced anthesis-silking interval, increased ears per plant, delayed senescence and relatively high leaf chlorophyll during late grain filling [88]. Drought at one of the sensitive growth stages, caused up to 40% grain yield losses. However, prolonged water stress during tasseling and ear formation stages leads to yield loss of 66–93% greater magnitude [39].

#### **3.1 Effect of nitrogen at vegetative stage under drought stress**

Variation in N supply affects both growth and development of maize plants [89]. Uhart and Andrade [90] reported that N deprivation reduced leaf area index, leaf area duration, radiation interception, and radiation use efficiency. However, nitrogen fertilizer changes canopy size which has an effect on the radiation use efficiency (RUE) of the crop thus affect plant growth and productivity [91]. According to Bänziger et al. [92], about 50% of all N in the leaf is directly involved

**451**

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

in photosynthesis as either enzymes or chlorophyll. Thus, if the N supply is insufficient, photosynthesis is decreased by reducing the leaf area and photosynthesis rate as well as accelerating leaf senescence. Longer duration of green leaf area is one of the most important ways to improve maize yields. Bertin and Gallais [93] found that leaf senescence was highly correlated with a nitrogen nutrition index, mainly at low levels of nitrogen input. Using a comparative proteomic analysis of *Zea mays*, Prinsi et al. [94] found that the nitrogen status of plants may affect the post-translational modification of phosphoenolpyruvate carboxylase (PEPCase) that plays a role in phosphorylation in leaves. Several studies have reported that drought stress decreases N uptake and assimilation in plants [24, 95, 96]. Maize growth and many physiological processes associated with it are enhanced by N supply [97]. Nitrogen efficiency is a complex trait, to identify for N-efficiency 16 tropical maize cultivars, studied for leaf senescence under N deficiency (short-term nutrient solution experiment). Leaf chlorophyll contents and photosynthesis rates were used as measures for leaf senescence. The results show that the photosynthetic capacity of senescing leaves correlated with the N efficiency of the cultivars, rather than leaf chlorophyll content [98]. The effect of nitrogen on maize leaves at three level of drought stress (normal, mild, and severe stress) was examined, The NO content and nitrate reductase (NR) activity of maize leaves were significantly reduced under drought stress, while moderate nitrogen supply promoted the accumulation of NO and an increase in the Nitrate Reductase activity. Also, abscisic acid content increased and was positively correlated with the nitrogen concentration under drought stress. Together, these results indicate that moderate nitrogen supply increases plant resistance to drought stress, while high or low nitrogen concentrations increase the sensitivity of maize to drought stress [99]. Maize (*Zea mays* L.) crop was subjected to different periods of deficit irrigation and N rates in the field. The results indicated that optimum use of both water supply and N application will maximize the maize production. Deficit irrigation during early vegetative growth modestly reduced LAI, plant height, CGR, N uptake and total biomass production as compared to reproductive stage [100] also N uptake decreased with greater water and N deficits. Two maize hybrids differencing resistance to drought were fertilized with two different forms of nitrogen fertilizers, Ca(NO3)2 and (NH4)2 SO4, and after fourth leaf stage they were exposed to drought stress. The results shows that two maize hybrids different in adaptability to two nitrogen treatment. NH4 treated plants maintain the high turgor by improved osmotic adjustment under drought stress. Whereas, chlorophyll a, b values significantly higher in NH4 treated plants compared to NH3 treated plants in which chlorophyll content decreased throughout the drought stress [23]. Similar work Zhang et al. [101] indicated increased NO3 nutrition played a favored anti-oxidative metabolic role, as compared with NH4 nutrition, in the plants thereby increasing tolerance to drought stress. Further, two maize genotypes were accessed for effect of nitrogen rates and water stress. Under water stress, Shaadan 9 accumulates higher dry matter, grain yield, anti-oxidative enzyme activity, and lower MDA content than Shaadan 911. However, the addition of nitrogen increased dry matter and grain yield as well as activities of SOD, POD, and CAT to different levels and significantly decreased MDA content under water stress, higher for Shaandan 911 than for Shaandan 9. Thus, drought-sensitive variety showed its full potential after adding nitrogen in water stress condition [102]. The dry matter accumulation and nitrogen uptake were compared in sorghum and maize. Drought reduced nitrogen availability in soil for both the crops, although sensitivity of maize crop to nitrogen is more. Directly, maize crop shows less accumulation of dry matter in water deficit condition and indirectly because of nitrogen nutrition [103]. Twenty maize inbred lines were phenotype in response to two levels of water and nitrogen supply (control and stress) and combined nitrogen and water

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

#### *Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

in photosynthesis as either enzymes or chlorophyll. Thus, if the N supply is insufficient, photosynthesis is decreased by reducing the leaf area and photosynthesis rate as well as accelerating leaf senescence. Longer duration of green leaf area is one of the most important ways to improve maize yields. Bertin and Gallais [93] found that leaf senescence was highly correlated with a nitrogen nutrition index, mainly at low levels of nitrogen input. Using a comparative proteomic analysis of *Zea mays*, Prinsi et al. [94] found that the nitrogen status of plants may affect the post-translational modification of phosphoenolpyruvate carboxylase (PEPCase) that plays a role in phosphorylation in leaves. Several studies have reported that drought stress decreases N uptake and assimilation in plants [24, 95, 96]. Maize growth and many physiological processes associated with it are enhanced by N supply [97]. Nitrogen efficiency is a complex trait, to identify for N-efficiency 16 tropical maize cultivars, studied for leaf senescence under N deficiency (short-term nutrient solution experiment). Leaf chlorophyll contents and photosynthesis rates were used as measures for leaf senescence. The results show that the photosynthetic capacity of senescing leaves correlated with the N efficiency of the cultivars, rather than leaf chlorophyll content [98]. The effect of nitrogen on maize leaves at three level of drought stress (normal, mild, and severe stress) was examined, The NO content and nitrate reductase (NR) activity of maize leaves were significantly reduced under drought stress, while moderate nitrogen supply promoted the accumulation of NO and an increase in the Nitrate Reductase activity. Also, abscisic acid content increased and was positively correlated with the nitrogen concentration under drought stress. Together, these results indicate that moderate nitrogen supply increases plant resistance to drought stress, while high or low nitrogen concentrations increase the sensitivity of maize to drought stress [99]. Maize (*Zea mays* L.) crop was subjected to different periods of deficit irrigation and N rates in the field. The results indicated that optimum use of both water supply and N application will maximize the maize production. Deficit irrigation during early vegetative growth modestly reduced LAI, plant height, CGR, N uptake and total biomass production as compared to reproductive stage [100] also N uptake decreased with greater water and N deficits. Two maize hybrids differencing resistance to drought were fertilized with two different forms of nitrogen fertilizers, Ca(NO3)2 and (NH4)2 SO4, and after fourth leaf stage they were exposed to drought stress. The results shows that two maize hybrids different in adaptability to two nitrogen treatment. NH4 treated plants maintain the high turgor by improved osmotic adjustment under drought stress. Whereas, chlorophyll a, b values significantly higher in NH4 treated plants compared to NH3 treated plants in which chlorophyll content decreased throughout the drought stress [23]. Similar work Zhang et al. [101] indicated increased NO3 nutrition played a favored anti-oxidative metabolic role, as compared with NH4 nutrition, in the plants thereby increasing tolerance to drought stress. Further, two maize genotypes were accessed for effect of nitrogen rates and water stress. Under water stress, Shaadan 9 accumulates higher dry matter, grain yield, anti-oxidative enzyme activity, and lower MDA content than Shaadan 911. However, the addition of nitrogen increased dry matter and grain yield as well as activities of SOD, POD, and CAT to different levels and significantly decreased MDA content under water stress, higher for Shaandan 911 than for Shaandan 9. Thus, drought-sensitive variety showed its full potential after adding nitrogen in water stress condition [102]. The dry matter accumulation and nitrogen uptake were compared in sorghum and maize. Drought reduced nitrogen availability in soil for both the crops, although sensitivity of maize crop to nitrogen is more. Directly, maize crop shows less accumulation of dry matter in water deficit condition and indirectly because of nitrogen nutrition [103]. Twenty maize inbred lines were phenotype in response to two levels of water and nitrogen supply (control and stress) and combined nitrogen and water

*Abiotic Stress in Plants*

**3. Nutrient status in drought**

The role of N metabolism regulation in maize drought tolerance was comprehensively studied [74]. Drought have strong impact on all the physiological process of plants and N metabolism is of central importance during drought stress because to survive drought and to maintain growth plants adaptive strategies includes such as improved nutrient uptake and transport, photosynthesis regulation, and to produced solutes and proteins that contains N compounds such as amino acids, amides and betaines. While Kant et al. [75] reported that relationship between drought and N nutrition consists of a complex network of regulatory interactions that affects almost all physiological processes in plants. Nitrogen (N) is one of the macronutrients, its major requirement for crop growth and grain yield of maize, whereas maize water requirement is highest in the reproductive stage [76]. Therefore, nitrogen and water separately or in combination are two are most critical factors in maize production. According to Saud et al. [77] the use of nutritional soil with a proper nitrogen rate remained effective in ameliorating the adverse influence of drought stress. However, a contrast study showed low field capacity irrigation and low nitrogen fertilizer rates application improves water use efficiency and nitrogen recovery efficiency (NRE) simultaneously [78]. Water and nutrient availability influence root system architecture and development [79, 80]. During vegetative stages of corn, under moderate drought stress rooting depth typically increases, allowing more efficient uptake of water and nutrients from deeper within the soil profile [81]. The increase in plant height related with increasing N fertilizer application under drought stress [82, 83]. Andrade [84] reported that N deprivation reduced leaf area index, leaf area duration, radiation interception, and radiation use efficiency. Improved tolerance to various abiotic stresses alternative breeding strategies are adopted, one of them is to select and inbreed maize plants under high population density to improved tolerance for low-N and drought [85]. Although under dense plant population maize prone to lodging due to increase in plant height and reduced culum diameters makes the stem weaker [86]. The mechanism underlying tolerance to high population density and low-N diverse tropical germplasm were grown under optimal, high plant population density and low-N. The association between ASI and grain yield, delayed senescence (expressed as chlorophyll concentration or number of green leaves above the ear) and ear/tassel weight ratio was observed in low-N. Also, grain yield negatively correlated with abortion rate. While under optimal and high population density, a positive association was reported between ovule number and abortion rate, suggesting a source limitation for C products [87]. In the same way selection of hybrid progenies for mid-season drought tolerance was due to improvements in morpho-physiological secondary traits such as reduced anthesis-silking interval, increased ears per plant, delayed senescence and relatively high leaf chlorophyll during late grain filling [88]. Drought at one of the sensitive growth stages, caused up to 40% grain yield losses. However, prolonged water stress during tasseling and ear formation stages leads to

**450**

yield loss of 66–93% greater magnitude [39].

**3.1 Effect of nitrogen at vegetative stage under drought stress**

Variation in N supply affects both growth and development of maize plants [89]. Uhart and Andrade [90] reported that N deprivation reduced leaf area index, leaf area duration, radiation interception, and radiation use efficiency. However, nitrogen fertilizer changes canopy size which has an effect on the radiation use efficiency (RUE) of the crop thus affect plant growth and productivity [91]. According to Bänziger et al. [92], about 50% of all N in the leaf is directly involved

deficit. Image analyses study provide the opportunity for new traits, identified several color-related traits and kinetic chlorophyll fluorescence (PSII). For biomass production ability in maize, kinetic chlorophyll fluorescence (PSII) is relevant traits particularly under severe stress conditions. While architectural traits, like greater leaf area which provide good discrimination of resistant cultivars to abiotic stresses under climate change scenarios [104].

#### **3.2 Effect of nitrogen at reproductive stage under water deficit condition**

Maize crop tolerant to N-deficit conditions at early vegetative stage than later reproductive phase [105]. There is a synergistic relationship between water availability and N use efficiency in maize [106]. When N supply is limited, grain yield is more associated with N deficiency than drought stress, but with adequate N supply, drought stress is the main yield-limiting factor [97]. Similarly Halvorson et al. [107] described maize yield as a function of available water and nitrogen. Maize plants selected for tolerance to mid-season drought also provide tolerance toward nitrogen stress. This may be due to an increase in both the number of kernels per plant and kernel weight. Hence consistently increases grain yield across N-level [108]. The pre-anthesis drought significantly reduced the number of kernel rows, the number of kernels per row, as well as the 1000-kernel weight. The 80 kg N ha−1 was sufficient to achieve maximum grain yield under pre-anthesis drought. It is hypothesized that the adverse effects of pre-anthesis drought on grain yield can be mitigated if varieties are selected for roots which rapidly penetrate the soil and exploit the water resources in deep soil layers [109]. The effects of water stress imposed at low-sensitive growth stages (vegetative, reproductive, and both vegetative and reproductive) and level of nitrogen (N) supply (100 and 200 kg ha−1) on the physiological and agronomic characteristics of the two hybrids of maize (*Zea mays* L.) were studied. The results showed that proline content increased and the relative water content, leaf greenness, 100-kernel weight, and grain yield decreased under conditions of water deficits. The limited irrigation imposed on maize during reproductive stage resulted in more yield reduction than that during vegetative stage. The 100-kernel weight was the most sensitive yield component to determine the yield variation in maize plant when the WD treatments were imposed in lowsensitive growth stages. The increase of N supply improved yield and IWUE when maize plant endured once irrigation shortage at vegetative stage. But, the performance of high N fertilizer reduced and eliminated when water deficit imposed once at reproductive stage and twice at vegetative and reproductive stages, respectively [110]. Further, the hybrids B73 × LH38, FS854, B73 × Mol7, and US13 were subjected to drought stress from the seventh leaf stage to evaluate differences in carbon and nitrogen accumulation and partitioning under drought. The results indicate that the greater drought tolerance of B73 × LH38 and FS854 to stress imposed during vegetative and early reproductive development resulted from their more active N uptake and assimilation and sugar production during the later portion of grain fill and from their more efficient partitioning of assimilate to the developing kernels [111]. Drought severity decreased grain yield sharply, but grain yield increased with nitrogen fertilizer. The time taken for pollination, grain weight, and total number of grains/ear were also affected. Increased proline content significantly under drought stress conditions shows activation of osmotic adjustment mechanism [112]. In a field study (carried out from 1995 to 1997) the effect of irrigation and water stress imposed at different development stages on vegetative growth, grain yield and other yield components of corn (*Zea mays* L.) was determined. The results of this 3-year study show that water stress occurring during vegetative and tasseling stages reduced plant height, and also leaf area development. Short-duration water

**453**

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

deficits during the rapid vegetative growth period caused 28–32% loss of final dry matter weight. Whereas, single irrigation omission during one of the sensitive growth stages, caused up to 40% grain yield losses. Although prolonged water stress during tasseling and ear formation stages the predictable loss could be much greater (66–93%) [39]. Though, stay-green and kernel numbers are affected by nitrogen uptake and use efficiency, and by nitrogen remobilization [113]. Whereas, insufficient N supply combined with water deficit reduces per-plant kernel number and mass, total aboveground dry matter (DM) yield, and harvest index (HI) [114, 115].

Higher plants are heterotrophic, leaves are the major organs that are photosynthetically active sources with tissues that synthesize sugars and translocate mainly sucrose to other parts of the plants, which are photosynthetically less active or inactive sinks such as roots, fruits kernel, and tubers. This physiological dynamics is not static and changes with each different phonological stages. The plant life cycle begin from embryo (sink) that mobilize nutrient from storage organ seed (source). During vegetative stage the source organ are photosynthesizing leaves (fixed CO2 + H2O = sugars) that export carbohydrates to various developing sink organs, like, emerging leaves, roots for their utilization in growth and development. During reproductive stage, sugars and other nutrients are mobilized from mature leaves to developing seeds, kernel, fruits, and tubers. This sink transition and various competing sinks changes with respect to sink strength and all compete for carbohydrates allocation. This carbohydrate production (source) and carbohydrate partitioning (sink utilization of carbon) is also influence with various other factors such as nutrients, hormones, environmental factors. This coordinate regulation of source activity and sink strength determine the carbon © allocation throughout the plant and has been crucial for defining yield of the crop [116]. The balance between source-sink is disturbed due to insufficient sink strength or slow carbohydrates export leading to accumulation of carbohydrates in source organ causes feedback inhibition which in turn, down regulate the photosynthesis in leaves [117]. Drought, modify source-sink relations that disturb plant growth, also adaptation to stress and consequently affect crop productivity. Source-sink altered under water deficit condition because the growth primacies of plant changes. Since the source organ unable to supply assimilates to various competitive vegetative organ growth, to maintain reproductive structures and adaptation to stress. This decrease in photo assimilates reduces sink number and size [118]. They also emphasize the role of several metabolic and hormonal factors influencing not only the source strength, but especially the sink activity and their interrelations and their potential to improve yield stability under drought and salinity stresses. Further, Fahad et al. [10] highlighted the regulatory circuits of different phytohormones and cross talks among ABA, indole ABA, CKs, GA, SA, BRs, JA, ETHY, and TR at physiological and molecular levels on exposure to salinity. The decline in source and sink strengths during water deficit leads to important reductions in crop yield [3]. In the present climate change model [119], drought periods are becoming more frequent and severe [120, 121], and future crop varieties have to be more resilient to this stress. Maize is the third most important crop after wheat and rice, mainly grown for food, feed, and fodder. Plant breeding and agronomic practices have major role in genetic contribution to improved grain yield. Two main important physiological processes involved are sustained leaf photosynthesis during grain filling, which contributes to increases in dry matter accumulation, and second, an increase in kernel number due to higher partitioning to the kernels during the sensitive period of kernel number

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

**4. Source-sink relationship under drought**

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

deficits during the rapid vegetative growth period caused 28–32% loss of final dry matter weight. Whereas, single irrigation omission during one of the sensitive growth stages, caused up to 40% grain yield losses. Although prolonged water stress during tasseling and ear formation stages the predictable loss could be much greater (66–93%) [39]. Though, stay-green and kernel numbers are affected by nitrogen uptake and use efficiency, and by nitrogen remobilization [113]. Whereas, insufficient N supply combined with water deficit reduces per-plant kernel number and mass, total aboveground dry matter (DM) yield, and harvest index (HI) [114, 115].

#### **4. Source-sink relationship under drought**

*Abiotic Stress in Plants*

under climate change scenarios [104].

deficit. Image analyses study provide the opportunity for new traits, identified several color-related traits and kinetic chlorophyll fluorescence (PSII). For biomass production ability in maize, kinetic chlorophyll fluorescence (PSII) is relevant traits particularly under severe stress conditions. While architectural traits, like greater leaf area which provide good discrimination of resistant cultivars to abiotic stresses

**3.2 Effect of nitrogen at reproductive stage under water deficit condition**

Maize crop tolerant to N-deficit conditions at early vegetative stage than later reproductive phase [105]. There is a synergistic relationship between water availability and N use efficiency in maize [106]. When N supply is limited, grain yield is more associated with N deficiency than drought stress, but with adequate N supply, drought stress is the main yield-limiting factor [97]. Similarly Halvorson et al. [107] described maize yield as a function of available water and nitrogen. Maize plants selected for tolerance to mid-season drought also provide tolerance toward nitrogen stress. This may be due to an increase in both the number of kernels per plant and kernel weight. Hence consistently increases grain yield across N-level [108]. The pre-anthesis drought significantly reduced the number of kernel rows, the number of kernels per row, as well as the 1000-kernel weight. The 80 kg N ha−1 was sufficient to achieve maximum grain yield under pre-anthesis drought. It is hypothesized that the adverse effects of pre-anthesis drought on grain yield can be mitigated if varieties are selected for roots which rapidly penetrate the soil and exploit the water resources in deep soil layers [109]. The effects of water stress imposed at low-sensitive growth stages (vegetative, reproductive, and both vegetative and reproductive) and level of nitrogen (N) supply (100 and 200 kg ha−1) on the physiological and agronomic characteristics of the two hybrids of maize (*Zea mays* L.) were studied. The results showed that proline content increased and the relative water content, leaf greenness, 100-kernel weight, and grain yield decreased under conditions of water deficits. The limited irrigation imposed on maize during reproductive stage resulted in more yield reduction than that during vegetative stage. The 100-kernel weight was the most sensitive yield component to determine the yield variation in maize plant when the WD treatments were imposed in lowsensitive growth stages. The increase of N supply improved yield and IWUE when maize plant endured once irrigation shortage at vegetative stage. But, the performance of high N fertilizer reduced and eliminated when water deficit imposed once at reproductive stage and twice at vegetative and reproductive stages, respectively [110]. Further, the hybrids B73 × LH38, FS854, B73 × Mol7, and US13 were subjected to drought stress from the seventh leaf stage to evaluate differences in carbon and nitrogen accumulation and partitioning under drought. The results indicate that the greater drought tolerance of B73 × LH38 and FS854 to stress imposed during vegetative and early reproductive development resulted from their more active N uptake and assimilation and sugar production during the later portion of grain fill and from their more efficient partitioning of assimilate to the developing kernels [111]. Drought severity decreased grain yield sharply, but grain yield increased with nitrogen fertilizer. The time taken for pollination, grain weight, and total number of grains/ear were also affected. Increased proline content significantly under drought stress conditions shows activation of osmotic adjustment mechanism [112]. In a field study (carried out from 1995 to 1997) the effect of irrigation and water stress imposed at different development stages on vegetative growth, grain yield and other yield components of corn (*Zea mays* L.) was determined. The results of this 3-year study show that water stress occurring during vegetative and tasseling stages reduced plant height, and also leaf area development. Short-duration water

**452**

Higher plants are heterotrophic, leaves are the major organs that are photosynthetically active sources with tissues that synthesize sugars and translocate mainly sucrose to other parts of the plants, which are photosynthetically less active or inactive sinks such as roots, fruits kernel, and tubers. This physiological dynamics is not static and changes with each different phonological stages. The plant life cycle begin from embryo (sink) that mobilize nutrient from storage organ seed (source). During vegetative stage the source organ are photosynthesizing leaves (fixed CO2 + H2O = sugars) that export carbohydrates to various developing sink organs, like, emerging leaves, roots for their utilization in growth and development. During reproductive stage, sugars and other nutrients are mobilized from mature leaves to developing seeds, kernel, fruits, and tubers. This sink transition and various competing sinks changes with respect to sink strength and all compete for carbohydrates allocation. This carbohydrate production (source) and carbohydrate partitioning (sink utilization of carbon) is also influence with various other factors such as nutrients, hormones, environmental factors. This coordinate regulation of source activity and sink strength determine the carbon © allocation throughout the plant and has been crucial for defining yield of the crop [116]. The balance between source-sink is disturbed due to insufficient sink strength or slow carbohydrates export leading to accumulation of carbohydrates in source organ causes feedback inhibition which in turn, down regulate the photosynthesis in leaves [117]. Drought, modify source-sink relations that disturb plant growth, also adaptation to stress and consequently affect crop productivity. Source-sink altered under water deficit condition because the growth primacies of plant changes. Since the source organ unable to supply assimilates to various competitive vegetative organ growth, to maintain reproductive structures and adaptation to stress. This decrease in photo assimilates reduces sink number and size [118]. They also emphasize the role of several metabolic and hormonal factors influencing not only the source strength, but especially the sink activity and their interrelations and their potential to improve yield stability under drought and salinity stresses. Further, Fahad et al. [10] highlighted the regulatory circuits of different phytohormones and cross talks among ABA, indole ABA, CKs, GA, SA, BRs, JA, ETHY, and TR at physiological and molecular levels on exposure to salinity. The decline in source and sink strengths during water deficit leads to important reductions in crop yield [3]. In the present climate change model [119], drought periods are becoming more frequent and severe [120, 121], and future crop varieties have to be more resilient to this stress. Maize is the third most important crop after wheat and rice, mainly grown for food, feed, and fodder. Plant breeding and agronomic practices have major role in genetic contribution to improved grain yield. Two main important physiological processes involved are sustained leaf photosynthesis during grain filling, which contributes to increases in dry matter accumulation, and second, an increase in kernel number due to higher partitioning to the kernels during the sensitive period of kernel number

#### *Abiotic Stress in Plants*

determination. Water use in corn is greatest during the late vegetative through early grain filling stages [76]. There are several factors that contribute to high plant performance under drought stress, like better portioning of biomass to the developing ear that results in faster spikelet growth which may results reduction in the number spikelet formed on the ear thus, facilitate overall seed set by reducing water and carbon stress per spikelet [122].

#### **4.1 Source limitation and strength under drought stress**

#### *4.1.1 Source limitation*

Growth conditions are favorable during pre-flowering and flowering, and a certain maize crop therefore establishes a large leaf area and many kernels and ears. Drought occurs after flowering causing the leaves to senesce early. The supply of assimilates will limit grain yield in this crop, and the plant will have many small kernels, thus limiting the source.

#### *4.1.2 Regulation of source activity*

Leaves are the main source organs; in maize, leaves ranged from 8 to 20 and these are present alternatively on nodes, and drought stress reduced the leaf size and number of leaves. Alternatively, reduced leaf areas under drought stress consider as an adaptive strategy. This may reduce the plant water requirement by reducing the leaf area and probability of plant survival is increased under limited water availability [123] but decrease in chlorophyll contents, chloroplast contents and photosynthetic activity reduced the grain yield [124, 125]. The important characteristics of superior germplasm include, more biomass allocation to leaf relative to stem weight, more leaf area, longer active leaf area duration [126] under different growing conditions. However features like morpho-physiological attributes such as leaf area, chlorophyll content, the rate and duration of photosynthesis, time of flowering, dry matter partitioning during silking, and leaf stay green plays key role in dry matter accumulation, harvest index and grain yield of corn [127]. Selection for stress tolerance has improved the grain yield in maize and it depends on higher leaf area per plant and higher harvest index (HI). Moreover, "stay green trait" or leaf greenness or reduction in the rate of leaf senescence during grain filling was one of the distinctions between older and newer hybrids [128]. Lafitte and Edmeades [129] selected maize cultivars in low and high N and secondary traits (Such as increased plant height, leaf area, chlorophyll concentrations, and delayed senescence) to improved grain yields. However, selection based in low-N to increase grain yield disturbs the balance of source and sink. Various secondary traits like water depletion pattern, leaf rolling, canopy temperature, reveals root potential and water extraction capacity. Whereas chlorophyll concentration quantifies the stay green trait of leaf. Flowering traits are associated with specific developmental stage, while, photosynthetic rate indicates the plant growth rate throughout the plant life cycle. Thus, these secondary traits are a related to specific mechanism and they contribute to enhance grain yield under drought stress [130]. Monneveux et al. [131] indicate that the traits of source organs contribute marginally to drought tolerance; variation of leaf or root traits seems to be less important than variation in tassel parameters for increasing drought tolerance. Further progress in drought tolerance in maize, the solution might reside in the manipulation of sink organs. It is therefore suggested that selection for even greater number of ears, bigger grains and smaller tassels may help to increase grain yield under water limited environments in the near future. Selection based on crop ideotype by Bolaños and Edmeades [132]

**455**

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

the determination of maize potential sink capacity and final KW.

**4.2 Sink limitation and strength under drought stress**

*4.2.1 Sink limitation*

thus limiting the sink.

*4.2.2 Regulation of sink activity*

was successful in producing drought-tolerant cultivars that were able to partition the assimilates to ear at flowering. However, Gambin et al. [133] indicated maize reproductive efficiency in kernel set is not constant across different plant growth rates (PGR) around flowering, therefore PGR per kernel used during this period as an indicator of source availability per kernel. The curvilinear response relating kernel number per plant and PGR around flowering, increased PGRs resulted in higher PGR per kernel around this period (r2 = 0.86; p < 0.001). Grain filling duration was partially explained (r2 = 0.27; p < 0.01) by the ratio between PGR per kernel during the effective grain filling period and kernel growth rate. Together, these results support the importance of source availability per kernel during early grain filling on

Growth conditions are favorable during pre-flowering and a certain maize crop therefore establishes a large leaf area. There is stress during flowering time and therefore the crop can establish only few ears and kernels. After flowering, the growing conditions may be favorable again, but the demand for assimilates by the kernels and their capacity to absorb the available assimilate will limit grain yield,

Flowering is the most crucial stage for silk growth, pollination, and kernel setting in maize [134] and is the utmost susceptible stage to drought stress. An asynchrony between silk emergence and pollen shedding under drought stress before and during flowering increases the anthesis-silking interval (ASI) and primarily causes yield loss [135–138]. High-temperature stress also hampered the pollen characteristics. However, exogenous application of various PGRs significantly reduced the damaging effects of high temperature, compared with control. Further, pollen characteristics can be exploited as screening tools for varietal development but selection must focus for those germplasm sources which can tolerate temperature above 38°C [1, 11, 12]. Under drought stress, a positive correlation was observed between flowering and kernel number per plant (r > 0.8), barrenness (r > 0.7), and ASI (r = \_0.4 to \_0.7) in tropical maize [136]. In maize, increased abiotic stress tolerance increased yield and yield stability in some tropical and temperate maize germplasm [139, 140]. Canadian maize hybrids show increased tolerance toward various stress factors like high population density, weed interference, low night temperature, low soil moisture, and low-N stress due to the features such as increased leaf longevity, increased nutrient and water uptake, and greater assimilates supply during grain filling [140]. Similarly, tropical maize shows decreased kernel and ear abortion, selected for mid-season drought [141, 142]. Therefore, constitutive stress-tolerance mechanism may be operative in maize germplasm, which may be related to the creation of sink size [92]. The ovule, ear and kernels are the reproductive sinks, for their proper development assimilates supply above threshold level are necessary. In unstressed condition, ear abortion may occurs due to insufficient assimilates supply that led to barren plants. Thus, ovule fails to extrude silk due to slow growth, whereas kernel aborted following pollination [141, 143, 144]. The corn was subjected to low water potential (Cw) for 5 days at the time of pollination [145]. Zinselmeier et al. [145] observed that embryos formed but abortion occurred and kernel number decreased markedly. Besides, during this

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

was successful in producing drought-tolerant cultivars that were able to partition the assimilates to ear at flowering. However, Gambin et al. [133] indicated maize reproductive efficiency in kernel set is not constant across different plant growth rates (PGR) around flowering, therefore PGR per kernel used during this period as an indicator of source availability per kernel. The curvilinear response relating kernel number per plant and PGR around flowering, increased PGRs resulted in higher PGR per kernel around this period (r2 = 0.86; p < 0.001). Grain filling duration was partially explained (r2 = 0.27; p < 0.01) by the ratio between PGR per kernel during the effective grain filling period and kernel growth rate. Together, these results support the importance of source availability per kernel during early grain filling on the determination of maize potential sink capacity and final KW.

#### **4.2 Sink limitation and strength under drought stress**

#### *4.2.1 Sink limitation*

*Abiotic Stress in Plants*

carbon stress per spikelet [122].

kernels, thus limiting the source.

*4.1.2 Regulation of source activity*

*4.1.1 Source limitation*

**4.1 Source limitation and strength under drought stress**

determination. Water use in corn is greatest during the late vegetative through early grain filling stages [76]. There are several factors that contribute to high plant performance under drought stress, like better portioning of biomass to the developing ear that results in faster spikelet growth which may results reduction in the number spikelet formed on the ear thus, facilitate overall seed set by reducing water and

Growth conditions are favorable during pre-flowering and flowering, and a certain maize crop therefore establishes a large leaf area and many kernels and ears. Drought occurs after flowering causing the leaves to senesce early. The supply of assimilates will limit grain yield in this crop, and the plant will have many small

Leaves are the main source organs; in maize, leaves ranged from 8 to 20 and these are present alternatively on nodes, and drought stress reduced the leaf size and number of leaves. Alternatively, reduced leaf areas under drought stress consider as an adaptive strategy. This may reduce the plant water requirement by reducing the leaf area and probability of plant survival is increased under limited water availability [123] but decrease in chlorophyll contents, chloroplast contents and photosynthetic activity reduced the grain yield [124, 125]. The important characteristics of superior germplasm include, more biomass allocation to leaf relative to stem weight, more leaf area, longer active leaf area duration [126] under different growing conditions. However features like morpho-physiological attributes such as leaf area, chlorophyll content, the rate and duration of photosynthesis, time of flowering, dry matter partitioning during silking, and leaf stay green plays key role in dry matter accumulation, harvest index and grain yield of corn [127]. Selection for stress tolerance has improved the grain yield in maize and it depends on higher leaf area per plant and higher harvest index (HI). Moreover, "stay green trait" or leaf greenness or reduction in the rate of leaf senescence during grain filling was one of the distinctions between older and newer hybrids [128]. Lafitte and Edmeades [129] selected maize cultivars in low and high N and secondary traits (Such as increased plant height, leaf area, chlorophyll concentrations, and delayed senescence) to improved grain yields. However, selection based in low-N to increase grain yield disturbs the balance of source and sink. Various secondary traits like water depletion pattern, leaf rolling, canopy temperature, reveals root potential and water extraction capacity. Whereas chlorophyll concentration quantifies the stay green trait of leaf. Flowering traits are associated with specific developmental stage, while, photosynthetic rate indicates the plant growth rate throughout the plant life cycle. Thus, these secondary traits are a related to specific mechanism and they contribute to enhance grain yield under drought stress [130]. Monneveux et al. [131] indicate that the traits of source organs contribute marginally to drought tolerance; variation of leaf or root traits seems to be less important than variation in tassel parameters for increasing drought tolerance. Further progress in drought tolerance in maize, the solution might reside in the manipulation of sink organs. It is therefore suggested that selection for even greater number of ears, bigger grains and smaller tassels may help to increase grain yield under water limited environments in the near future. Selection based on crop ideotype by Bolaños and Edmeades [132]

**454**

Growth conditions are favorable during pre-flowering and a certain maize crop therefore establishes a large leaf area. There is stress during flowering time and therefore the crop can establish only few ears and kernels. After flowering, the growing conditions may be favorable again, but the demand for assimilates by the kernels and their capacity to absorb the available assimilate will limit grain yield, thus limiting the sink.

#### *4.2.2 Regulation of sink activity*

Flowering is the most crucial stage for silk growth, pollination, and kernel setting in maize [134] and is the utmost susceptible stage to drought stress. An asynchrony between silk emergence and pollen shedding under drought stress before and during flowering increases the anthesis-silking interval (ASI) and primarily causes yield loss [135–138]. High-temperature stress also hampered the pollen characteristics. However, exogenous application of various PGRs significantly reduced the damaging effects of high temperature, compared with control. Further, pollen characteristics can be exploited as screening tools for varietal development but selection must focus for those germplasm sources which can tolerate temperature above 38°C [1, 11, 12]. Under drought stress, a positive correlation was observed between flowering and kernel number per plant (r > 0.8), barrenness (r > 0.7), and ASI (r = \_0.4 to \_0.7) in tropical maize [136]. In maize, increased abiotic stress tolerance increased yield and yield stability in some tropical and temperate maize germplasm [139, 140]. Canadian maize hybrids show increased tolerance toward various stress factors like high population density, weed interference, low night temperature, low soil moisture, and low-N stress due to the features such as increased leaf longevity, increased nutrient and water uptake, and greater assimilates supply during grain filling [140]. Similarly, tropical maize shows decreased kernel and ear abortion, selected for mid-season drought [141, 142]. Therefore, constitutive stress-tolerance mechanism may be operative in maize germplasm, which may be related to the creation of sink size [92]. The ovule, ear and kernels are the reproductive sinks, for their proper development assimilates supply above threshold level are necessary. In unstressed condition, ear abortion may occurs due to insufficient assimilates supply that led to barren plants. Thus, ovule fails to extrude silk due to slow growth, whereas kernel aborted following pollination [141, 143, 144]. The corn was subjected to low water potential (Cw) for 5 days at the time of pollination [145]. Zinselmeier et al. [145] observed that embryos formed but abortion occurred and kernel number decreased markedly. Besides, during this

abortion, all of the intermediates in starch synthesis were depleted and the starch contained in the ovary almost disappeared. The period for ovule, kernel, and ear abortion falls 1 week before until 2 weeks after silking; during this period, stress factors like drought, shade, high density, and low-N stress accelerate these processes [27, 90, 146, 147]. Physiological reasons for abortion of reproductive structures under various stresses have shown that concurrent photosynthesis is required to maintain the flux of carbohydrates to the young ear around flowering but under drought it not possible to remobilize carbohydrate reserve for the support of ear development [148–150]. Drought also reduces invertase activity in ovaries and this will reduce the flux of hexose sugars; starch reserves of ovaries are depleted and it leads to the ovaries abortion [151]. In tropics, maize yield could be increased by improving the balance between the source supply and sink demand [152]. The main focus of maize breeding program is to increase the grain yield under high N; this practice resulted in an increase in both the source and sink in size and efficiency [153]. However, in N-limited conditions, not only the importance of C but also for N associates with source and sink [154] the N required during the exponential phase of grain growth to sustain the kernel number per plant and grain yield. The role of glutamine synthetase (GS) and asparagine synthetase (AS) (their main function in plant nitrogen remobilization) was determined in two maize varieties (ZD958 and NH101) in relation to post-silking drought stress (PD) nitrogen partitioning. The results indicate the PD stress increased nitrogen remobilization, and in ear leaves, the expression of *ZmGln1-3* was enhanced for both varieties. While under PD treatment, three AS genes (*ZmAS1, ZmAS2*, and 10 *ZmAS3*) were differentially regulated, of which the expression of *ZmAS3* was stimulated at the late stage of leaf senescence. In developing kernels, there were no significant differences in expression patterns of GS and AS genes between the well water (WW) and PD plants. Therefore, at the whole plant level, PD stress showed more influence on leaf nitrogen status, and the upregulation of GS and AS genes may contribute to the higher leaf nitrogen remobilization when exposed to PD treatments [155]. Genotypes selected for high grain yield under normal growing conditions also had a high level of dry-matter accumulation and partitioned more assimilates to the grain under water deficit conditions. The improved genotypes produced more numbers of ears/plant and kernels/ear [156]. Leaf growth and ASI are the main determinants of source and sink strengths of maize.

#### **Author details**

Suphia Rafique Division of Plant Physiology, IARI, Pusa Campus, New Delhi, India

\*Address all correspondence to: suphia123@gmail.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**457**

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

[9] Fahad S, Bano A. Effect of salicylic acid on physiological and biochemical characterization of maize grown in saline area. Pakistan Journal of Botany.

[10] Fahad S, Hussain S, Matloob A, Khan FA, Khaliq A, Saud S, et al. Phytohormones and plant responses to salinity stress: A review. Plant Growth Regulation. 2014b;**75**(2):391-404. DOI:

10.1007/s10725-014-0013-y

[11] Fahad S, Hussain S, Saud S, Tanveer M, Bajwa AA, Hassan S, et al. A biochar application protects rice pollen from high-temperature stress. Plant Physiology and Biochemistry.

[12] Fahad S, Nie L, Chen Y, Wu C, Xiong D, Saud S, et al. Crop plant hormones and environmental stress. Sustainable Agriculture Reviews.

[13] Fahad S, Hussain S, Saud S, Hassan S, Ihsan Z, Shah AN, et al. Exogenously applied plant growth regulators enhance the morphophysiological growth and yield of rice under high temperature. Frontiers in Plant Science. 2016c;**7**:1250

[14] Coruzzi G, Bush DR. Nitrogen and carbon nutrient and metabolite signalling in plants. Plant Physiology.

[15] Coruzzi GM. Primary N-assimilation into amino acids in Arabidopsis. In: Somerville CR, Meyerowitz EM, editors. The Arabidopsis Book. Rockville, MD, USA: American Society of Plant Biologists; 2003. DOI: 10.1199/tab.0010. Available from: http://www.aspb.org/

2012;**44**:1433-1438

2015a;**96**:281-287

2015b;**15**:371-400

2001;**125**:61-64

publications/Arabidopsis

[16] Miller AJ, Fan X, Orsel M,

Botany. 2007;**58**:2297-2306

Smith SJ, Wells DM. Nitrate transport and signalling. Journal of Experimental

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

[1] Fahad S, Muhammad ZI, Abdul K, Ihsanullah D, Saud S, Saleh A, et al. Consequences of high temperature under changing climate optima for rice pollen characteristics - Concepts

Agronomy and Soil Science. 2018. DOI:

[2] Mittler R. Abiotic stress, the field environment and stress combination. Trends in Plant Science. 2006;**11**:15-19

[4] Mishra AK, Singh VP. A review of drought concepts. Journal of Hydrology.

[5] Chen H, Sun J. Changes in drought characteristics over China using the standardized precipitation evapotranspiration index. Journal of

[6] Maiti RK, Satya P. Research advances in major cereal crops for adaptation to abiotic stresses. GM Crops & Food.

[7] Banziger M, Edmeades GO, Beck D, Bellon M. Breeding for Drought and Nitrogen Stress Tolerance in Maize: From Theory to Practice. Mexico, D.F.:

[8] Song J, Zhou JC, Zhou WW, Xu HL, Wang FX, Xu YG, et al. Effects of salinity and nitrate on production and germination of dimorphic seeds both applied through the mother plant and exogenously during germination in *Suaeda salsa*. Plant Species Biology.

Climate. 2015;**28**(13):281-299

2014;**5**(4):259-279

CIMMYT; 2000

2016;**31**:19-28

and perspectives. Archives of

10.1080/03650340.2018.1443213

[3] Fahad S, Bajwa AA, Nazir U, Anjum SA, Farooq A, Zohaib A, et al. Crop production under drought and heat stress: Plant responses and management options. Frontiers in Plant Science. 2017;**8**:1147. DOI: 10.3389/

fpls.2017.01147

2010;**391**(1-2):202-216

**References**

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

#### **References**

*Abiotic Stress in Plants*

**456**

**Author details**

source and sink strengths of maize.

Suphia Rafique

Division of Plant Physiology, IARI, Pusa Campus, New Delhi, India

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

abortion, all of the intermediates in starch synthesis were depleted and the starch contained in the ovary almost disappeared. The period for ovule, kernel, and ear abortion falls 1 week before until 2 weeks after silking; during this period, stress factors like drought, shade, high density, and low-N stress accelerate these processes [27, 90, 146, 147]. Physiological reasons for abortion of reproductive structures under various stresses have shown that concurrent photosynthesis is required to maintain the flux of carbohydrates to the young ear around flowering but under drought it not possible to remobilize carbohydrate reserve for the support of ear development [148–150]. Drought also reduces invertase activity in ovaries and this will reduce the flux of hexose sugars; starch reserves of ovaries are depleted and it leads to the ovaries abortion [151]. In tropics, maize yield could be increased by improving the balance between the source supply and sink demand [152]. The main focus of maize breeding program is to increase the grain yield under high N; this practice resulted in an increase in both the source and sink in size and efficiency [153]. However, in N-limited conditions, not only the importance of C but also for N associates with source and sink [154] the N required during the exponential phase of grain growth to sustain the kernel number per plant and grain yield. The role of glutamine synthetase (GS) and asparagine synthetase (AS) (their main function in plant nitrogen remobilization) was determined in two maize varieties (ZD958 and NH101) in relation to post-silking drought stress (PD) nitrogen partitioning. The results indicate the PD stress increased nitrogen remobilization, and in ear leaves, the expression of *ZmGln1-3* was enhanced for both varieties. While under PD treatment, three AS genes (*ZmAS1, ZmAS2*, and 10 *ZmAS3*) were differentially regulated, of which the expression of *ZmAS3* was stimulated at the late stage of leaf senescence. In developing kernels, there were no significant differences in expression patterns of GS and AS genes between the well water (WW) and PD plants. Therefore, at the whole plant level, PD stress showed more influence on leaf nitrogen status, and the upregulation of GS and AS genes may contribute to the higher leaf nitrogen remobilization when exposed to PD treatments [155]. Genotypes selected for high grain yield under normal growing conditions also had a high level of dry-matter accumulation and partitioned more assimilates to the grain under water deficit conditions. The improved genotypes produced more numbers of ears/plant and kernels/ear [156]. Leaf growth and ASI are the main determinants of

\*Address all correspondence to: suphia123@gmail.com

provided the original work is properly cited.

[1] Fahad S, Muhammad ZI, Abdul K, Ihsanullah D, Saud S, Saleh A, et al. Consequences of high temperature under changing climate optima for rice pollen characteristics - Concepts and perspectives. Archives of Agronomy and Soil Science. 2018. DOI: 10.1080/03650340.2018.1443213

[2] Mittler R. Abiotic stress, the field environment and stress combination. Trends in Plant Science. 2006;**11**:15-19

[3] Fahad S, Bajwa AA, Nazir U, Anjum SA, Farooq A, Zohaib A, et al. Crop production under drought and heat stress: Plant responses and management options. Frontiers in Plant Science. 2017;**8**:1147. DOI: 10.3389/ fpls.2017.01147

[4] Mishra AK, Singh VP. A review of drought concepts. Journal of Hydrology. 2010;**391**(1-2):202-216

[5] Chen H, Sun J. Changes in drought characteristics over China using the standardized precipitation evapotranspiration index. Journal of Climate. 2015;**28**(13):281-299

[6] Maiti RK, Satya P. Research advances in major cereal crops for adaptation to abiotic stresses. GM Crops & Food. 2014;**5**(4):259-279

[7] Banziger M, Edmeades GO, Beck D, Bellon M. Breeding for Drought and Nitrogen Stress Tolerance in Maize: From Theory to Practice. Mexico, D.F.: CIMMYT; 2000

[8] Song J, Zhou JC, Zhou WW, Xu HL, Wang FX, Xu YG, et al. Effects of salinity and nitrate on production and germination of dimorphic seeds both applied through the mother plant and exogenously during germination in *Suaeda salsa*. Plant Species Biology. 2016;**31**:19-28

[9] Fahad S, Bano A. Effect of salicylic acid on physiological and biochemical characterization of maize grown in saline area. Pakistan Journal of Botany. 2012;**44**:1433-1438

[10] Fahad S, Hussain S, Matloob A, Khan FA, Khaliq A, Saud S, et al. Phytohormones and plant responses to salinity stress: A review. Plant Growth Regulation. 2014b;**75**(2):391-404. DOI: 10.1007/s10725-014-0013-y

[11] Fahad S, Hussain S, Saud S, Tanveer M, Bajwa AA, Hassan S, et al. A biochar application protects rice pollen from high-temperature stress. Plant Physiology and Biochemistry. 2015a;**96**:281-287

[12] Fahad S, Nie L, Chen Y, Wu C, Xiong D, Saud S, et al. Crop plant hormones and environmental stress. Sustainable Agriculture Reviews. 2015b;**15**:371-400

[13] Fahad S, Hussain S, Saud S, Hassan S, Ihsan Z, Shah AN, et al. Exogenously applied plant growth regulators enhance the morphophysiological growth and yield of rice under high temperature. Frontiers in Plant Science. 2016c;**7**:1250

[14] Coruzzi G, Bush DR. Nitrogen and carbon nutrient and metabolite signalling in plants. Plant Physiology. 2001;**125**:61-64

[15] Coruzzi GM. Primary N-assimilation into amino acids in Arabidopsis. In: Somerville CR, Meyerowitz EM, editors. The Arabidopsis Book. Rockville, MD, USA: American Society of Plant Biologists; 2003. DOI: 10.1199/tab.0010. Available from: http://www.aspb.org/ publications/Arabidopsis

[16] Miller AJ, Fan X, Orsel M, Smith SJ, Wells DM. Nitrate transport and signalling. Journal of Experimental Botany. 2007;**58**:2297-2306

[17] Thum KE, Shasha DE, Lejay LV, Coruzzi GM. Light and carbon-signaling pathways. Modeling circuits of interactions. Plant Physiology. 2003;**132**:440-452

[18] Urbanczyk-Wochniak E, Fernie AR. Metabolic profiling reveals altered nitrogen nutrient regimes have diverse effects on the metabolism of hydroponically-grown tomato (*Solanum lycopersicum*) plants. Journal of Experimental Botany. 2005;**56**:309-321

[19] Gutiérrez RA et al. Systems approach identifies an organic nitrogenresponsive gene network that is regulated by the master clock control gene CCA1. Proceedings of the National Academy of Sciences of the United States of America. 2008;**105**:4939-4944

[20] Aziz K, Daniel KYT, Muhammad ZA, Honghai L, Shahbaz AT, Mir A, et al. Nitrogen fertility and abiotic stresses management in cotton crop: A review. Environmental Science and Pollution Research. 2017b;**24**:14551-14566. DOI: 10.1007/s11356-017-8920-x

[21] Aziz K, Daniel KYT, Fazal M, Muhammad ZA, Farooq S, Fan W, et al. Nitrogen nutrition in cotton and control strategies for greenhouse gas emissions: A review. Environmental Science and Pollution Research. 2017a;**24**:23471- 23487. DOI: 10.1007/s11356-017-0131-y

[22] Donald CM, Hamblin J. The biological yield and harvest index of cereal as agronomics and plant breeding criteria. Advances in Agronomy. 1976;**28**:361-405

[23] Mihailovic N, Jelic G, Filipovic R, Djurdjevic M, Dzeletovic Z. Effect of nitrogen form on maize response to drought stress. Plant and Soil. 1992;**144**:191-197

[24] Waraich EA, Ahmad R, Ashraf MY. Role of mineral nutrition in

alleviating drought stress in plants. Australian Journal of Crop Science. 2011;**5**(6):764-777

[25] Humbert S, Subedi S, Cohn J, Zeng B, Bi YM, Chen X, et al. Genomewide expression profiling of maize in response to individual and combined water and nitrogen stresses. BMC Genomics. 2013;**14**:3. DOI: 10.1186/1471-2164-14-3

[26] Claassen MM, Shaw RH. Water deficit effects on corn. I. Vegetative components. Agronomy Journal. 1970;**62**:652-655

[27] Grant RF, Jackson BS, Kiniry JR, Arkin GF. Water deficit timing effects on yield components in maize. Agronomy Journal. 1989;**81**:61-65

[28] Czyzewicz JR, Below FE. Genotypic variation for nitrogen uptake by maize kernels grown *in vitro*. Crop Science. 1994;**33**:491-497

[29] Boyer JS. Leaf enlargement and metabolic rates in corn, soybean and sunflower at various leaf water potentials. Plant Physiology. 1970;**46**:233-235

[30] Abrecht DG, Carberry PS. The influence of water deficit prior to tassel initiation on maize growth, development and yield. Field Crops Research. 1993;**3**(l):55-69

[31] Moss GI, Downey LA. Influence of drought stress on female gametophyte development in corn *(Zea mays* L.) and subsequent grain yield. Crop Science. 1971;**11**:368-372

[32] Watson DJ. The physiological basis of variation in yield. Advances in Agronomy. 1952;**4**:101-145

[33] NeSmith DS, Ritchie JT. Short-and long-term responses of corn to a preanthesis soil water deficit. Agronomy Journal. 1992a;**84**:107-113

**459**

2011a;**197**:177-185

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

[41] Cornic G. Drought stress inhibits photosynthesis by decreasing stomatal

[42] Meyer S, Genty B. Heterogenous inhibition of photosynthesis over the leaf surface of *Rosa rubinosa* L. during water stress and abscisic acid treatment: Induction of a metabolic component by limitation of CO2 diffusion. Planta.

[43] Lawlor DW. Carbon and nitrogen assimilation in relation to yield:

Mechanism is the key to understanding

Experimental Botany. 2002;**53**:773-787

[44] Medrano H, Parry MA, Socias X, Lawlor DW. Long term water stress inactivates Rubisco in subterranean clover. The Annals of Applied Biology.

[45] Tezara W, Mitchell V, Driscoll S, Lawlor D. Water stress inhibits plant photosynthesis by decreasing coupling factor and ATP. Nature. 1999;**401**:914-

production system. Journal of

aperture: Not by affecting ATP synthesis. Trends in Plant Science.

2000;**5**:187-188

1999;**210**:126-131

1997;**131**:491-501

917. DOI: 10.1038/44842

[46] O'Regan BP, Cress t WA, van Staden J. Root growth, water relations, abscisic acid and proline levels of drought-resistant and droughtsensitive maize cultivars in response to water stress. South African Journal of

Botany. 1993;**59**(1):98-104

1993;**85**:1159-1164

pbi.2007.04.014

[47] Jama AO, Ottman MJ. Timing of the first irrigation in corn and water stress conditioning. Agronomy Journal.

[48] Seki M, Umezawa T, Urano K, Shinozaki K. Regulatory metabolic networks in drought stress responses. Current Opinion in Plant Biology. 2007;**10**:296-302. DOI: 10.1016/j.

[49] Bray EA. Classification of genes differentially expressed during

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

[34] Xiangbo Z, Lei L, Lai J, Zhao H, Song W. Effects of drought stress and water recovery on physiological responses and gene expression in maize seedlings. BMC Plant Biology.

[35] Egilla JN, Davies FT, Boutton TW. Drought stress influences leaf water content, photosynthesis, and water use efficiency of *Hibiscus rosa-sinensis* at three potassium concentrations. Photosynthetica. 2005;**43**(1):135-140

[36] Abdul Jaleel C, Manivannan P, Kishorekumar A, Sankar B, Gopi R, Somasundaram R, et al. Alterations in osmoregulation, antioxidant enzymes and indole alkaloid levels in *Catharanthus roseus* exposed to water deficit, colloids and surfaces. Biointerfaces. 2008;**59**:150-157

[37] Ali Q, Ali A, Waseem M, Muzaffar A, Ahmed S, Ali S, et al. Correlation analysis for morphophysiological traits of maize (*Zea mays* L.). Life Science Journal. 2014,

[38] Nepolean T, Singh I, Hussain F,

Molecular characterization and assessment of genetic variability of inbred line showing genetic variability

for drought tolerance in maize. Journal of Plant Biochemistry and Biotechnology. 2013;**22**:71-79

[39] Çakir R. Effect of water stress at different development stages on vegetative and reproductive growth of corn. Field Crops Research. 2004;**89**: 1-16. DOI: 10.1016/j.fcr.2004.01.005

[40] Anjum SA, Wang LC, Farooq M, Hussain M, Xue LL, Zou CM.

Brassinolide application improves the drought tolerance in maize through modulation of enzymatic antioxidants and Leaf gas exchange. Journal of Agronomy and Crop Science.

2014;**11**(12s)

Pandey N, Gupta HS.

2018;**18**(68):2-16

#### *Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

[34] Xiangbo Z, Lei L, Lai J, Zhao H, Song W. Effects of drought stress and water recovery on physiological responses and gene expression in maize seedlings. BMC Plant Biology. 2018;**18**(68):2-16

*Abiotic Stress in Plants*

[17] Thum KE, Shasha DE, Lejay LV, Coruzzi GM. Light and carbon-signaling pathways. Modeling

circuits of interactions. Plant Physiology. 2003;**132**:440-452

*lycopersicum*) plants. Journal of

[19] Gutiérrez RA et al. Systems

responsive gene network that is regulated by the master clock control gene CCA1. Proceedings of the National Academy of Sciences of the United States of America. 2008;**105**:4939-4944

[20] Aziz K, Daniel KYT, Muhammad ZA, Honghai L, Shahbaz AT, Mir A, et al. Nitrogen fertility and abiotic stresses

10.1007/s11356-017-8920-x

[21] Aziz K, Daniel KYT, Fazal M, Muhammad ZA, Farooq S, Fan W, et al. Nitrogen nutrition in cotton and control strategies for greenhouse gas emissions: A review. Environmental Science and Pollution Research. 2017a;**24**:23471- 23487. DOI: 10.1007/s11356-017-0131-y

[22] Donald CM, Hamblin J. The biological yield and harvest index of cereal as agronomics and plant breeding

criteria. Advances in Agronomy.

[23] Mihailovic N, Jelic G, Filipovic R, Djurdjevic M, Dzeletovic Z. Effect of nitrogen form on maize response to drought stress. Plant and Soil.

[24] Waraich EA, Ahmad R, Ashraf MY.

Role of mineral nutrition in

1976;**28**:361-405

1992;**144**:191-197

[18] Urbanczyk-Wochniak E, Fernie AR. Metabolic profiling reveals altered nitrogen nutrient regimes have diverse effects on the metabolism of hydroponically-grown tomato (*Solanum*  alleviating drought stress in plants. Australian Journal of Crop Science.

[25] Humbert S, Subedi S, Cohn J, Zeng B, Bi YM, Chen X, et al. Genomewide expression profiling of maize in response to individual and

combined water and nitrogen stresses. BMC Genomics. 2013;**14**:3. DOI:

[26] Claassen MM, Shaw RH. Water deficit effects on corn. I. Vegetative components. Agronomy Journal.

[27] Grant RF, Jackson BS, Kiniry JR, Arkin GF. Water deficit timing effects on yield components in maize. Agronomy Journal. 1989;**81**:61-65

[28] Czyzewicz JR, Below FE. Genotypic variation for nitrogen uptake by maize kernels grown *in vitro*. Crop Science.

[29] Boyer JS. Leaf enlargement and metabolic rates in corn, soybean and sunflower at various leaf water potentials. Plant Physiology.

[30] Abrecht DG, Carberry PS. The influence of water deficit prior to tassel initiation on maize growth, development and yield. Field Crops

[31] Moss GI, Downey LA. Influence of drought stress on female gametophyte development in corn *(Zea mays* L.) and subsequent grain yield. Crop Science.

[32] Watson DJ. The physiological basis of variation in yield. Advances in

[33] NeSmith DS, Ritchie JT. Short-and long-term responses of corn to a preanthesis soil water deficit. Agronomy

Agronomy. 1952;**4**:101-145

Journal. 1992a;**84**:107-113

Research. 1993;**3**(l):55-69

2011;**5**(6):764-777

10.1186/1471-2164-14-3

1970;**62**:652-655

1994;**33**:491-497

1970;**46**:233-235

1971;**11**:368-372

Experimental Botany. 2005;**56**:309-321

approach identifies an organic nitrogen-

management in cotton crop: A review. Environmental Science and Pollution Research. 2017b;**24**:14551-14566. DOI:

**458**

[35] Egilla JN, Davies FT, Boutton TW. Drought stress influences leaf water content, photosynthesis, and water use efficiency of *Hibiscus rosa-sinensis* at three potassium concentrations. Photosynthetica. 2005;**43**(1):135-140

[36] Abdul Jaleel C, Manivannan P, Kishorekumar A, Sankar B, Gopi R, Somasundaram R, et al. Alterations in osmoregulation, antioxidant enzymes and indole alkaloid levels in *Catharanthus roseus* exposed to water deficit, colloids and surfaces. Biointerfaces. 2008;**59**:150-157

[37] Ali Q, Ali A, Waseem M, Muzaffar A, Ahmed S, Ali S, et al. Correlation analysis for morphophysiological traits of maize (*Zea mays* L.). Life Science Journal. 2014, 2014;**11**(12s)

[38] Nepolean T, Singh I, Hussain F, Pandey N, Gupta HS. Molecular characterization and assessment of genetic variability of inbred line showing genetic variability for drought tolerance in maize. Journal of Plant Biochemistry and Biotechnology. 2013;**22**:71-79

[39] Çakir R. Effect of water stress at different development stages on vegetative and reproductive growth of corn. Field Crops Research. 2004;**89**: 1-16. DOI: 10.1016/j.fcr.2004.01.005

[40] Anjum SA, Wang LC, Farooq M, Hussain M, Xue LL, Zou CM. Brassinolide application improves the drought tolerance in maize through modulation of enzymatic antioxidants and Leaf gas exchange. Journal of Agronomy and Crop Science. 2011a;**197**:177-185

[41] Cornic G. Drought stress inhibits photosynthesis by decreasing stomatal aperture: Not by affecting ATP synthesis. Trends in Plant Science. 2000;**5**:187-188

[42] Meyer S, Genty B. Heterogenous inhibition of photosynthesis over the leaf surface of *Rosa rubinosa* L. during water stress and abscisic acid treatment: Induction of a metabolic component by limitation of CO2 diffusion. Planta. 1999;**210**:126-131

[43] Lawlor DW. Carbon and nitrogen assimilation in relation to yield: Mechanism is the key to understanding production system. Journal of Experimental Botany. 2002;**53**:773-787

[44] Medrano H, Parry MA, Socias X, Lawlor DW. Long term water stress inactivates Rubisco in subterranean clover. The Annals of Applied Biology. 1997;**131**:491-501

[45] Tezara W, Mitchell V, Driscoll S, Lawlor D. Water stress inhibits plant photosynthesis by decreasing coupling factor and ATP. Nature. 1999;**401**:914- 917. DOI: 10.1038/44842

[46] O'Regan BP, Cress t WA, van Staden J. Root growth, water relations, abscisic acid and proline levels of drought-resistant and droughtsensitive maize cultivars in response to water stress. South African Journal of Botany. 1993;**59**(1):98-104

[47] Jama AO, Ottman MJ. Timing of the first irrigation in corn and water stress conditioning. Agronomy Journal. 1993;**85**:1159-1164

[48] Seki M, Umezawa T, Urano K, Shinozaki K. Regulatory metabolic networks in drought stress responses. Current Opinion in Plant Biology. 2007;**10**:296-302. DOI: 10.1016/j. pbi.2007.04.014

[49] Bray EA. Classification of genes differentially expressed during

water-deficit stress in *Arabidopsis thaliana*: An analysis using microarray and differential expression data. Annals of Botany (London). 2002;**9**:803-811

[50] Socias X, Correia MJ, Medrano H. The role of abscisic acid and water relations in drought responses of subterranean clover. Journal of Experimental Botany. 1987;**48**(311):1281-1288

[51] Hussain MA, Fahad S, Rahat S, Muhammad FJ, Muhammad M, Qasid A, et al. Multifunctional role of brassinosteroid and its analogues in plants. Plant Growth Regulation. 2020. DOI: 10.1007/s10725-020-00647-8

[52] Rhodes D, Samaras Y. Genetic control of osmoregulation in plants. In: Strange K, editor. Cellular and Molecular Physiology of Cell Volume Regulation. Boca Raton: CRC Press; 1994. pp. 347-361

[53] Bartels D, Sunkar R. Drought and salt tolerance in plants. Critical Reviews in Plant Sciences. 2005;**24**:23-58

[54] Mohammadkhani N, Heidari R. Effects of drought stress on soluble proteins in two maize varieties. Turkish Journal of Biology. 2008;**32**:23-30

[55] Munns R. Genes and salt tolerance: Bringing them together. The New Phytologist. 2005;**167**:645-663

[56] Hesham FA, Fahad S. Melatonin application enhances biochar efficiency for drought tolerance in maize varieties: Modifications in physio-biochemical machinery. Agronomy Journal. 2020:1-22

[57] Apel K, Hirt H. Reactive oxygen species: Metabolism, oxidative stress, and signal transduction. Annual Review of Plant Biology. 2004;**55**:373-399

[58] Yang L, Fountain JC, Wang H, Ni X, Ji P, Lee RD, et al. Stress sensitivity

is associated with differential accumulation of reactive oxygen and nitrogen species in maize genotypes with contrasting levels of drought tolerance. International Journal of Molecular Sciences. 2015;**16**:24791- 24819. DOI: 10.3390/ijms161024791

[59] Foyer Christine H, Valadier M-H, Migge A, Becke TW. Drought-induced effects on nitrate reductase activity and mRNA and on the coordination of nitrogen and carbon metabolism in maize leaves. Plant Physiology. 1998;**117**:283-292

[60] Nisar A, Malagoli M, Wirtz M, Hell R. Drought stress in maize causes differential acclimation responses of glutathione and sulfur metabolism in leaves and roots. BMC Plant Biology. 2016;**16**:247

[61] Bai LP, Sui FG, Ge TD, Sun ZH, Lu YY, Zhou GS. Effect of soil drought stress on leaf water status, membrane permeability and enzymatic antioxidant system of maize. Pedosphere. 2006;**16**:326-332

[62] Saab IN, Sharp RE, Pritchard J, Voetberg GS. Increased endogenous abscisic acid maintains primary root growth and inhibits shoot growth of maize seedlings at low water potentials. Plant Physiology. 1990;**93**:1329-1336

[63] Zhang L, Gao M, Hu J, Zhang X, Wang K. Ashraf M (2012) modulation role of abscisic acid (ABA) on growth, water relations and glycinebetaine metabolism in two maize (*Zea mays* L.) cultivars under drought stress. International Journal of Molecular Sciences. 2012;**13**:3189-3202

[64] Saud S, Chen Y, Fahad S, Hussain S, Na L, Xin L, et al. Silicate application increases the photosynthesis and its associated metabolic activities in Kentucky bluegrass under drought stress and post-drought recovery. Environmental Science and Pollution

**461**

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

[73] Chen D, Wang S, Cao B, Cao D, Leng G, Li H, et al. Genotypic variation in growth and physiological response to drought stress and re-watering reveals the critical role of recovery in drought adaptation in maize seedlings. Frontiers in Plant Science. 2016;**6**:1241. DOI:

[74] Wang H, Yang Z, Yu Y, Chen S, He Z, Wang Y, et al. Drought enhances nitrogen uptake and assimilation in maize roots. Agronomy Journal.

[75] Kant S, Bi YM, Rothstein SJ. Understanding plant response to

DOI: 10.1093/jxb/erq297

fpls.2017.00983

nitrogen limitation for the improvement of crop nitrogen use efficiency. Journal of Experimental Botany. 2011;**6**:1-11.

[76] Kranz WL, Irmak S, van Donk SJ, Yonts CD, Martin DL. Irrigation Management for Corn. Neb Guide (G1367-A). University of Nebraska Extension; 2008. Available from: http:// ianrpubs.unl.edu/live/g1850/build/ g1850.pdf (Accessed: 18 January 2018)

[77] Saud S, Fahad S, Yajun C, Ihsan MZ, Hammad HM, Nasim W, et al. Effects of nitrogen supply on water stress and recovery mechanisms in Kentucky bluegrass plants. Frontiers in Plant Science. 2017;**8**:983. DOI: 10.3389/

[78] Hafiz MH, Wajid F, Farhat A, Fahad S, Shafqat S, Wajid N, et al. Maize plant nitrogen uptake dynamics at limited irrigation water and nitrogen. Environmental Science and Pollution Research. 2016;**24**(3):2549-2557. DOI:

10.1007/s11356-016-8031-0

[79] Dwyer LM, Stewart DW. Effect of leaf age and position on net photosynthetic rates in maize (*Zea mays* L.). Agricultural and Forest Meteorology. 1986;**37**:29-46

[80] Lynch JP. Steep, cheap and deep: An ideotype to optimize water and

10.3389/fpls.2015.01241

2017;**109**(1):39-46

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

Research. 2016;**23**(17):17647-17655. DOI: 10.1007/s11356-016-6957-x

[65] Zhu J, Brown KM, Lynch JP. Root cortical aerenchyma improves the drought tolerance of maize (*Zea mays* L.)

[66] Chimungu JG, Brown KM, Lynch JP. Large root cortical cell size improves drought tolerance in maize. Plant Physiology. 2014;**166**:2014

[67] Anjum SA, Ashraf U, Tanveer M, Khan I, Hussain S, Shahzad B, et al. Drought induced changes in growth, osmolyte accumulation and antioxidant metabolism of three maize hybrids. Frontiers in Plant Science. 2017;**8**:69

[68] Chan EK, Rowe HC, Hansen BG, Kliebenstein DJ. The complex genetic architecture of the metabolome. PLoS

[69] Keurentjes JJ, Fu J, De Vos CR, Lommen A, Hall RD, Bino RJ, et al. The genetics of plant metabolism. Nature

[70] Meyer RC, Steinfath M, Lisec J, Becher M, Witucka-Wall H, Torjek O, et al. The metabolic signature related to high plant growth rate in *Arabidopsis thaliana*. Proceedings of the National Academy of Sciences of the United States of America. 2007;**104**:4759-4764

Genetics. 2010;**6**:e1001198

Genetics. 2006;**38**:842-849

[71] Riedelsheimer C, Lisec J, Czedik-Eysenberg A, Sulpice R, Flis A, Grieder C, et al. Genome-wide association mapping of leaf metabolic profiles for dissecting complex traits in maize. Proceedings of the National Academy of Sciences of the United States of America. 2012;**109**:8872-8877

[72] Sharma S, Thakur S, Kaur N, Pathania A. QTL mapping for abiotic stress tolerance in maize: A brief review. International Journal of Chemical Studies. 2018;**7**(1):1206-1209

*Plant*. Cell and Environment.

2010;**33**:740-749

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

Research. 2016;**23**(17):17647-17655. DOI: 10.1007/s11356-016-6957-x

*Abiotic Stress in Plants*

water-deficit stress in *Arabidopsis thaliana*: An analysis using microarray and differential expression data. Annals of Botany (London). 2002;**9**:803-811

is associated with differential accumulation of reactive oxygen and nitrogen species in maize genotypes with contrasting levels of drought tolerance. International Journal of Molecular Sciences. 2015;**16**:24791- 24819. DOI: 10.3390/ijms161024791

[59] Foyer Christine H, Valadier M-H, Migge A, Becke TW. Drought-induced effects on nitrate reductase activity and mRNA and on the coordination of nitrogen and carbon metabolism in maize leaves. Plant Physiology.

[60] Nisar A, Malagoli M, Wirtz M, Hell R. Drought stress in maize causes differential acclimation responses of glutathione and sulfur metabolism in leaves and roots. BMC Plant Biology.

[61] Bai LP, Sui FG, Ge TD, Sun ZH, Lu YY, Zhou GS. Effect of soil drought stress on leaf water status, membrane permeability and enzymatic antioxidant

[62] Saab IN, Sharp RE, Pritchard J, Voetberg GS. Increased endogenous abscisic acid maintains primary root growth and inhibits shoot growth of maize seedlings at low water potentials. Plant Physiology. 1990;**93**:1329-1336

[63] Zhang L, Gao M, Hu J, Zhang X, Wang K. Ashraf M (2012) modulation role of abscisic acid (ABA) on growth, water relations and glycinebetaine metabolism in two maize (*Zea mays* L.)

[64] Saud S, Chen Y, Fahad S, Hussain S, Na L, Xin L, et al. Silicate application increases the photosynthesis and its associated metabolic activities in Kentucky bluegrass under drought stress and post-drought recovery. Environmental Science and Pollution

cultivars under drought stress. International Journal of Molecular Sciences. 2012;**13**:3189-3202

system of maize. Pedosphere.

1998;**117**:283-292

2016;**16**:247

2006;**16**:326-332

[50] Socias X, Correia MJ, Medrano H. The role of abscisic acid and water relations in drought responses of subterranean clover. Journal of Experimental Botany.

1987;**48**(311):1281-1288

1994. pp. 347-361

[51] Hussain MA, Fahad S, Rahat S, Muhammad FJ, Muhammad M, Qasid A, et al. Multifunctional role of brassinosteroid and its analogues in plants. Plant Growth Regulation. 2020. DOI: 10.1007/s10725-020-00647-8

[52] Rhodes D, Samaras Y. Genetic control of osmoregulation in plants. In: Strange K, editor. Cellular and Molecular Physiology of Cell Volume Regulation. Boca Raton: CRC Press;

[53] Bartels D, Sunkar R. Drought and salt tolerance in plants. Critical Reviews

[54] Mohammadkhani N, Heidari R. Effects of drought stress on soluble proteins in two maize varieties. Turkish Journal of Biology. 2008;**32**:23-30

[55] Munns R. Genes and salt tolerance: Bringing them together. The New Phytologist. 2005;**167**:645-663

[56] Hesham FA, Fahad S. Melatonin application enhances biochar efficiency for drought tolerance in maize varieties: Modifications in physio-biochemical machinery. Agronomy Journal.

[57] Apel K, Hirt H. Reactive oxygen species: Metabolism, oxidative stress, and signal transduction. Annual Review of Plant Biology. 2004;**55**:373-399

[58] Yang L, Fountain JC, Wang H, Ni X, Ji P, Lee RD, et al. Stress sensitivity

in Plant Sciences. 2005;**24**:23-58

**460**

2020:1-22

[65] Zhu J, Brown KM, Lynch JP. Root cortical aerenchyma improves the drought tolerance of maize (*Zea mays* L.) *Plant*. Cell and Environment. 2010;**33**:740-749

[66] Chimungu JG, Brown KM, Lynch JP. Large root cortical cell size improves drought tolerance in maize. Plant Physiology. 2014;**166**:2014

[67] Anjum SA, Ashraf U, Tanveer M, Khan I, Hussain S, Shahzad B, et al. Drought induced changes in growth, osmolyte accumulation and antioxidant metabolism of three maize hybrids. Frontiers in Plant Science. 2017;**8**:69

[68] Chan EK, Rowe HC, Hansen BG, Kliebenstein DJ. The complex genetic architecture of the metabolome. PLoS Genetics. 2010;**6**:e1001198

[69] Keurentjes JJ, Fu J, De Vos CR, Lommen A, Hall RD, Bino RJ, et al. The genetics of plant metabolism. Nature Genetics. 2006;**38**:842-849

[70] Meyer RC, Steinfath M, Lisec J, Becher M, Witucka-Wall H, Torjek O, et al. The metabolic signature related to high plant growth rate in *Arabidopsis thaliana*. Proceedings of the National Academy of Sciences of the United States of America. 2007;**104**:4759-4764

[71] Riedelsheimer C, Lisec J, Czedik-Eysenberg A, Sulpice R, Flis A, Grieder C, et al. Genome-wide association mapping of leaf metabolic profiles for dissecting complex traits in maize. Proceedings of the National Academy of Sciences of the United States of America. 2012;**109**:8872-8877

[72] Sharma S, Thakur S, Kaur N, Pathania A. QTL mapping for abiotic stress tolerance in maize: A brief review. International Journal of Chemical Studies. 2018;**7**(1):1206-1209

[73] Chen D, Wang S, Cao B, Cao D, Leng G, Li H, et al. Genotypic variation in growth and physiological response to drought stress and re-watering reveals the critical role of recovery in drought adaptation in maize seedlings. Frontiers in Plant Science. 2016;**6**:1241. DOI: 10.3389/fpls.2015.01241

[74] Wang H, Yang Z, Yu Y, Chen S, He Z, Wang Y, et al. Drought enhances nitrogen uptake and assimilation in maize roots. Agronomy Journal. 2017;**109**(1):39-46

[75] Kant S, Bi YM, Rothstein SJ. Understanding plant response to nitrogen limitation for the improvement of crop nitrogen use efficiency. Journal of Experimental Botany. 2011;**6**:1-11. DOI: 10.1093/jxb/erq297

[76] Kranz WL, Irmak S, van Donk SJ, Yonts CD, Martin DL. Irrigation Management for Corn. Neb Guide (G1367-A). University of Nebraska Extension; 2008. Available from: http:// ianrpubs.unl.edu/live/g1850/build/ g1850.pdf (Accessed: 18 January 2018)

[77] Saud S, Fahad S, Yajun C, Ihsan MZ, Hammad HM, Nasim W, et al. Effects of nitrogen supply on water stress and recovery mechanisms in Kentucky bluegrass plants. Frontiers in Plant Science. 2017;**8**:983. DOI: 10.3389/ fpls.2017.00983

[78] Hafiz MH, Wajid F, Farhat A, Fahad S, Shafqat S, Wajid N, et al. Maize plant nitrogen uptake dynamics at limited irrigation water and nitrogen. Environmental Science and Pollution Research. 2016;**24**(3):2549-2557. DOI: 10.1007/s11356-016-8031-0

[79] Dwyer LM, Stewart DW. Effect of leaf age and position on net photosynthetic rates in maize (*Zea mays* L.). Agricultural and Forest Meteorology. 1986;**37**:29-46

[80] Lynch JP. Steep, cheap and deep: An ideotype to optimize water and

N acquisition by maize root systems. Annals of Botany. 2013;**112**:347-357

[81] Robertson WK, Hammond LC, Johnson JT, Boote KJ. Effects of plantwater stress on root distribution of corn, soybeans, and peanuts in sandy soil. Agronomy Journal. 1980;**72**:548-550

[82] Balko LG, Russell WA. Response of maize inbred lines to N fertilizer. Agronomy Journal. 1980;**72**:723-728

[83] Lucas EO. The effect of density and N fertilizer on growth and yield of maize (*Zea mays*, L.) in Nigeria. Journal of Agriculture Science (Cambridge). 1986;**107**:573-578

[84] Andrade FH. Analysis of growth and yield of maize, sunflower and soybean grown at Balcarce, Argentina. Field Crops Research. 1995a;**41**:1-12

[85] Vasal SK, Cordova HS, Beck DL, Edmeades GO. Choices among breeding procedures and strategies for developing stress tolerant maize germplasm. In: Edmeades GO, Bänziger M, Mickelson HR, Peña-Valdivia CB, editors. Developing Drought and Low N-Tolerant Maize. Proceedings of a Symposium; 25-29 March 1996; CIMMYT, El Batan, Mexico. Mexico D.F.: CIMMYT; 1997

[86] Kamarn M, Wenwen C, Irshad A, Xiangping M, Xudong Z, Wennan S, et al. Effect of paclobutrazol, a potential growth regulator on stalk mechanical strength, lignin accumulation and its relation with lodging resistance of maize. Plant Growth Regulation. 2017;**84**:317-332. DOI: 10.1007/ s10725-017-0342-8

[87] Monneveux P, Zaidi PH, Sanchez C. Population density and low nitrogen affects yield-associated traits in tropical maize. Crop Science. 2005;**45**:535-545

[88] Zaidi PH, Srinivasan G, Cordova HS, Sanchez C. Gains from improvement for mid-season drought tolerance in tropical maize (*Zea mays* L.). Field Crops Research. 2004;**89**:135-152

[89] McCullough DE, Girardin P, Mihajlovic M, Aguilera A, Tollenaar. Influence of N supply on development and dry matter accumulation of an old and new maize hybrid. Canadian Journal of Plant Science. 1994;**74**:471-477

[90] Uhart SA, Andrade FH. Nitrogen deficiency in maize: I. Effects on crop growth, development, dry matter partitioning. Crop Science. 1995a;**35**:1376-1383

[91] Wajid N, Ashfaq A, Asad A, Muhammad T, Muhammad A, Muhammad S, et al. Radiation efficiency and nitrogen fertilizer impacts on sunflower crop in contrasting environments of Punjab, Pakistan. Environmental Science and Pollution Research. 2017;**25**:1822-1836

[92] Benziger M, Edmeades GO, Lefitte HR. Physiological mechanism contributing to the increased n stress tolerance of tropical maize selected for drought tolerance. Field Crops Research. 2002;**75**:223-233

[93] Bertin P, Gallais A. Genetic variation for nitrogen use efficiency in a set of recombinant maize inbred lines. I. Agro-physiological results. Maydica. 2000;**45**:53-66

[94] Prinsi B, Negri AS, Pesaresi P, Cocucci M, Espen L. Evaluation of protein pat-tern changes in roots and leaves of *Zea mays* plants in response to nitrate availability by two-dimensional gel electrophoresis analysis. BMC Plant Biology. 2009;**9**:113

[95] Cramer MD, Hawkins H-J, Verboom GA. The importance of nutritional regulation of plant water

**463**

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

crops in different nitrogen and water supply conditions. Agronomie.

[104] Dodig D, Božinović S, Nikolić A, Zorić M, Vančetović J, Ignjatović-Micić D, et al. Image-derived traits related to mid-season growth performance of maize under nitrogen and water stress. Frontiers in Plant Science. 2019;**10**:814.

DOI: 10.3389/fpls.2019.00814

[105] Islam MR, Rahman SME, Rahman MM, Oh DH, Ra CS. The effects of biogas slurry on the

Forestry. 2010;**34**:91-99

2008;**100**:551-556

2006;**98**:63-71

2002;**75**:223-233

production and quality of maize fodder. Turkish Journal of Agriculture and

[106] Kim KI, Clay DE, Carlson CG, Clay SA, Trooien T. Do synergistic relationships between nitrogen and water influence the ability of corn to use nitrogen derived from fertilizer and soil? Agronomy Journal.

[107] Halvorson AD, Mosier AR, Reule CA, Bausch WC. Nitrogen and tillage effects on irrigated continuous corn yields. Agronomy Journal.

[108] Banziger M, Edmeades GO, Lafitte HR. Physiological mechanisms contributing to the increased N stress tolerance of tropical maize selected for drought tolerance. Field Crops Research.

[109] Moser SB, Feil B, Jampatong S, Stamp P. Effects of pre-anthesis drought, nitrogen fertilizer rate, and variety on grain yield, yield components, and harvest index of tropical maize. Agricultural Water Management. 2006;**81**:41-58. DOI: 10.

1016/j.agwat.2005.04.005

[110] Mansouri-Far C, Sanavy SA, Saberali SF. Maize yield response to deficit irrigation during low-sensitive growth stages and nitrogen rate

1996;**16**(4):231-246

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

flux. Oecologia. 2009;**161**:15-24. DOI:

[96] Sardans J, Penuelas J. The role of plants in the effects of global change on nutrient availability and stoichiometry

Physiology. 2012;**160**:1741-1761. DOI:

[98] Erley GS a'm, Begum N, Worku M, Bänziger M, Horst WJ. Leaf senescence induced by nitrogen deficiency as indicator of genotypic differences in nitrogen efficiency in tropical maize. Journal of Plant Nutrition and Soil

Xu ZZ, Zhou GS. Maize leaf functional responses to drought episode and rewatering. Agricultural and Forest Meteorology. 2018;**249**:57-70

10.1007/ s00442-009-1364-3

in the plant-soil system. Plant

[97] Eck HV. Irrigated corn yield response to nitrogen and water. Agronomy Journal. 1984;**76**:421-428

10.1104/pp.112.208785

Science. 2007;**170**:106-114

[99] Song H, Li YB, Zhou L,

[100] Pandey RK, Maranville JW, Admou A. Deficit irrigation and nitrogen effects on maize in a Sahelian environment. I. Grain yield and yield components. Agricultural Water Management. 2000a;**46**:1-13

[101] Zhang LX, Gao M, Li SQ, Li SX, Liang ZS. Water status and photosynthesis in two maize (*Zea mays* L.) cultivars as affected by supplied nitrogen form and drought stress. Pakistan Journal of Botany.

[102] Zhang LX, Li SX, Zhang H, Liang ZS. Nitrogen rates and water stress effects on production, lipid peroxidation and antioxidative enzyme activities in two maize (*Zea mays* L.) genotypes. Journal of Agronomy and Crop Science. 2007a;**193**:387-397

[103] Lemaire G, Charrier X. Nitrogen uptake capacities of maize and sorghum

2011;**43**:1995-2001

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

flux. Oecologia. 2009;**161**:15-24. DOI: 10.1007/ s00442-009-1364-3

*Abiotic Stress in Plants*

N acquisition by maize root systems. Annals of Botany. 2013;**112**:347-357

improvement for mid-season drought tolerance in tropical maize (*Zea mays* L.). Field Crops Research.

[89] McCullough DE, Girardin P, Mihajlovic M, Aguilera A, Tollenaar. Influence of N supply on development and dry matter accumulation of an old and new maize hybrid. Canadian Journal of Plant Science.

[90] Uhart SA, Andrade FH. Nitrogen deficiency in maize: I. Effects on crop growth, development, dry matter partitioning. Crop Science.

[91] Wajid N, Ashfaq A, Asad A, Muhammad T, Muhammad A,

and nitrogen fertilizer impacts on sunflower crop in contrasting environments of Punjab, Pakistan. Environmental Science and Pollution

Research. 2017;**25**:1822-1836

2002;**75**:223-233

2000;**45**:53-66

Biology. 2009;**9**:113

[92] Benziger M, Edmeades GO, Lefitte HR. Physiological mechanism contributing to the increased n stress tolerance of tropical maize selected for drought tolerance. Field Crops Research.

[93] Bertin P, Gallais A. Genetic variation for nitrogen use efficiency in a set of recombinant maize inbred lines. I. Agro-physiological results. Maydica.

[94] Prinsi B, Negri AS, Pesaresi P, Cocucci M, Espen L. Evaluation of protein pat-tern changes in roots and leaves of *Zea mays* plants in response to nitrate availability by two-dimensional gel electrophoresis analysis. BMC Plant

[95] Cramer MD, Hawkins H-J, Verboom GA. The importance of nutritional regulation of plant water

Muhammad S, et al. Radiation efficiency

2004;**89**:135-152

1994;**74**:471-477

1995a;**35**:1376-1383

[81] Robertson WK, Hammond LC, Johnson JT, Boote KJ. Effects of plantwater stress on root distribution of corn, soybeans, and peanuts in sandy soil. Agronomy Journal. 1980;**72**:548-550

[82] Balko LG, Russell WA. Response of maize inbred lines to N fertilizer. Agronomy Journal. 1980;**72**:723-728

[83] Lucas EO. The effect of density and N fertilizer on growth and yield of maize (*Zea mays*, L.) in Nigeria. Journal of Agriculture Science (Cambridge).

[84] Andrade FH. Analysis of growth and yield of maize, sunflower and soybean grown at Balcarce, Argentina. Field Crops Research. 1995a;**41**:1-12

[85] Vasal SK, Cordova HS, Beck DL, Edmeades GO. Choices among breeding procedures and strategies for developing

[86] Kamarn M, Wenwen C, Irshad A, Xiangping M, Xudong Z, Wennan S, et al. Effect of paclobutrazol, a potential growth regulator on stalk mechanical strength, lignin accumulation and its relation with lodging resistance of maize. Plant Growth Regulation. 2017;**84**:317-332. DOI: 10.1007/

[87] Monneveux P, Zaidi PH, Sanchez C. Population density and low nitrogen affects yield-associated traits in tropical maize. Crop Science. 2005;**45**:535-545

stress tolerant maize germplasm. In: Edmeades GO, Bänziger M, Mickelson HR, Peña-Valdivia CB, editors. Developing Drought and Low N-Tolerant Maize. Proceedings of a Symposium; 25-29 March 1996; CIMMYT, El Batan, Mexico. Mexico D.F.: CIMMYT; 1997

1986;**107**:573-578

**462**

s10725-017-0342-8

[88] Zaidi PH, Srinivasan G,

Cordova HS, Sanchez C. Gains from

[96] Sardans J, Penuelas J. The role of plants in the effects of global change on nutrient availability and stoichiometry in the plant-soil system. Plant Physiology. 2012;**160**:1741-1761. DOI: 10.1104/pp.112.208785

[97] Eck HV. Irrigated corn yield response to nitrogen and water. Agronomy Journal. 1984;**76**:421-428

[98] Erley GS a'm, Begum N, Worku M, Bänziger M, Horst WJ. Leaf senescence induced by nitrogen deficiency as indicator of genotypic differences in nitrogen efficiency in tropical maize. Journal of Plant Nutrition and Soil Science. 2007;**170**:106-114

[99] Song H, Li YB, Zhou L, Xu ZZ, Zhou GS. Maize leaf functional responses to drought episode and rewatering. Agricultural and Forest Meteorology. 2018;**249**:57-70

[100] Pandey RK, Maranville JW, Admou A. Deficit irrigation and nitrogen effects on maize in a Sahelian environment. I. Grain yield and yield components. Agricultural Water Management. 2000a;**46**:1-13

[101] Zhang LX, Gao M, Li SQ, Li SX, Liang ZS. Water status and photosynthesis in two maize (*Zea mays* L.) cultivars as affected by supplied nitrogen form and drought stress. Pakistan Journal of Botany. 2011;**43**:1995-2001

[102] Zhang LX, Li SX, Zhang H, Liang ZS. Nitrogen rates and water stress effects on production, lipid peroxidation and antioxidative enzyme activities in two maize (*Zea mays* L.) genotypes. Journal of Agronomy and Crop Science. 2007a;**193**:387-397

[103] Lemaire G, Charrier X. Nitrogen uptake capacities of maize and sorghum crops in different nitrogen and water supply conditions. Agronomie. 1996;**16**(4):231-246

[104] Dodig D, Božinović S, Nikolić A, Zorić M, Vančetović J, Ignjatović-Micić D, et al. Image-derived traits related to mid-season growth performance of maize under nitrogen and water stress. Frontiers in Plant Science. 2019;**10**:814. DOI: 10.3389/fpls.2019.00814

[105] Islam MR, Rahman SME, Rahman MM, Oh DH, Ra CS. The effects of biogas slurry on the production and quality of maize fodder. Turkish Journal of Agriculture and Forestry. 2010;**34**:91-99

[106] Kim KI, Clay DE, Carlson CG, Clay SA, Trooien T. Do synergistic relationships between nitrogen and water influence the ability of corn to use nitrogen derived from fertilizer and soil? Agronomy Journal. 2008;**100**:551-556

[107] Halvorson AD, Mosier AR, Reule CA, Bausch WC. Nitrogen and tillage effects on irrigated continuous corn yields. Agronomy Journal. 2006;**98**:63-71

[108] Banziger M, Edmeades GO, Lafitte HR. Physiological mechanisms contributing to the increased N stress tolerance of tropical maize selected for drought tolerance. Field Crops Research. 2002;**75**:223-233

[109] Moser SB, Feil B, Jampatong S, Stamp P. Effects of pre-anthesis drought, nitrogen fertilizer rate, and variety on grain yield, yield components, and harvest index of tropical maize. Agricultural Water Management. 2006;**81**:41-58. DOI: 10. 1016/j.agwat.2005.04.005

[110] Mansouri-Far C, Sanavy SA, Saberali SF. Maize yield response to deficit irrigation during low-sensitive growth stages and nitrogen rate

under semi-arid climatic conditions. Agricultural Water Management. 2010;**97**:12-22. DOI: 10.1016/j. agwat.2009.08.003

[111] Frederick JR, Below FE, Hesketh JD. Carbohydrate, nitrogen and dry matter accumulation and partitioning of maize hybrids under drought stress. Annals of Botany. 1990;**66**(4):407-415

[112] Tarighaleslami M, Zarghami R, Mashhadi M, Boojar A, Oveysi M. Effects of drought stress and different nitrogen levels on morphological traits of proline in leaf and protein of corn seed (*Zea mays* L.). American-Eurasian Journal of Agricultural & Environmental Sciences. 2012;**12**(1):49-56

[113] Gallais A, Hirel B. An approach to the genetics of nitrogen use efficiency in maize. Journal of Experimental Botany. 2004;**55**:295-306

[114] Boomsma CR, Santini JB, Tollenaar M, Vyn TJ. Maize morphophysiological responses to intense crowding and low nitrogen availability: An analysis and review. Agronomy Journal. 2009;**101**:1426-1452

[115] Chapuis R, Delluc C, Debeuf R, Tardieu F, Welcker C. Resiliences to water deficit in a phenotyping platform and in the field: How related are they in maize? European Journal of Agronomy. 2012;**42**:59-67

[116] Ruan YL. Sucrose metabolism: Gateway to diverse carbon use and sugar signaling. Annual Review of Plant Biology. 2014;**65**:33-67

[117] Rossi M, Bermudez L, Carrari F. Crop yield: Challenges from a metabolic perspective. Current Opinion in Plant Biology. 2015;**25**:79-89. DOI: 10.1016/j. pbi.2015. 05.004

[118] Albacete AA, Martínez-Andújar C, Pérez-Alfocea F. Hormonal and metabolic regulation of source-sink relations under salinity and drought: From plant survival to crop yield stability. Biotechnology Advances. 2013. DOI: 10.1016/j.biotechadv.2013.10.005

[119] IPCC. Climate change. Impacts, adaptation and vulnerability. In: Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE, editors. Contribution of Working Group II to the Fourth Assessment Report of the Inter-Governmental Panel on Climate Change. Cambridge: Cambridge University Press; 2007. p. 976

[120] Harrison MT, Tardieu F, Dong Z, Messina CD, Hammer GL. Characterizing drought stress and trait influence on maize yield under current and future conditions. Global Change Biology. 2014;**20**(3):867-878

[121] Ray DK, Mueller ND, West PC, Foley JA. Yield trends are insufficient to double global crop production by 2050. PLoS One. 2013;**8**:e66428. DOI: 10.1371/ journal.pone.0066428

[122] Bruce W, Edmeades G, Barker T. Molecular and physiological approaches to maize improvement for drought tolerance. Journal of Experimental Botany. 2002;**53**:13-25

[123] Belaygue C, Wery J, Cowan A, Tardieu F. Contribution of leaf expansion, rate of leaf appearance, and stolon branching to growth of plant leaf area under water deficit in white clover. Crop Science. 1996;**36**(5):1240-1246

[124] Flagella Z, Rotunno T, Tarantito E, Caterina RD, Caro AD. Changes in seed yield and oil fatty acid composition of high oleic sunflower (*Helianthus annuus* L.) hybrids in relation to the sowing date and the water regime. European Journal of Agronomy. 2002;**17**:221-230

**465**

press

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen…*

[134] Shaw RH. Climatic requirement. In: Sprague GF, editor. Maize and Maize Improvement. Agronomy Monographs 18. Madison, WI: ASA, CSSA, and

[135] Hall AJ, Vilella F, Trapani N, Chimenti C. The effects of water stress and genotype on the dynamics of pollen-shedding and silking in maize. Field Crops Research. 1982;**5**:349-363

[136] Bolaños J, Edmeades GO. The importance of the anthesis-silking interval in breeding for drought tolerance in tropical maize. Field Crops Research. 1996;**48**:65-80. DOI: 10.1016/0378-4290(96)00036-6

[137] Lu GH, Ren DL, Wang XQ,

[138] Ribaut JM, Hoisington DA, Deutsch JA, Jiang C, Gonzalez de Leon D. Identification of quantitative trait loci under drought conditions in tropical maize. 1. Flowering parameters and the anthesis-silking interval. Theoretical and Applied Genetics.

1996;**92**:905-914

Science. 1995;**35**:63-69

1999;**39**:1597-1604

1993;**33**:1029-1035

[140] Tollenaar M, Wu J. Yield improvement in temperate maize is attributable to greater water stress tolerance. Crop Science.

[141] Edmeades GO, Bolaños J, Hernandez M, Bello S. Causes for silk delay in a lowland tropical maize population. Crop Science.

[142] Chapman SC, Edmeades GO. Selection improves drought tolerance

Wu JK, Zhao MS. Evaluation on drought tolerance of maize hybrids in China. Journal of Maize Sciences. 2010;**3**:20-24

[139] Byrne PF, Bolaños J, Edmeades GO, Eaton DL. Gains from selection under drought versus multilocation testing in related tropical maize populations. Crop

SSSA; 1977. pp. 315-341

*DOI: http://dx.doi.org/10.5772/intechopen.93747*

[126] Zaidi PH, Srinivasan G, Sanchez C. Relationship between line per se and cross performance under low nitrogen fertility in tropical maize (*Zea mays* L.).

[127] Tollenaar M, Lee EA. Dissection of physiological processes underlying grain yield in maize by examining genetic improvement and heterosis. Maydica.

[128] Duvick DN, Smith JCS, Cooper M. Long-term selection in a commercial hybrid maize breeding program. Plant Breeding Reviews. 2004a;**24**:109-151

[129] Lafitte HR, Edmeades GO. Association between traits in tropical maize inbred lines and their hybrids under high and low soil nitrogen. Maydica. 1994;**40**:259-267

[130] Barker T, Campos H, Cooper M, Dolan D, Edmeades GO, Habben J, et al. Improving drought tolerance in maize. Plant Breeding Reviews. 2004;**25**, in

[131] Monneveuxi P, Sanchez C, Tiessen A. Future progress in drought tolerance in maize needs new secondary traits and cross combinations. Journal of Agricultural Science. 2008;**146**:287-300

[132] Bolaños J, Edmeades GO. Eight cycles of selection for drought tolerance in lowland tropical maize. II. Responses in reproductive behavior. Field Crops

[133] Gambín BL, Borrás L, Otegui ME. Source–sink relations and kernel weight differences in maize temperate hybrids. Field Crops Research. 2006;**95**:316-326

Research. 1993b;**31**:253-268

[125] Göksoya AT, Demirb AO, Turana ZM, Dağüstü N. Responses of sunflower (*Helianthus annuus* L.) to full and limited irrigation at different growth stages. Field Crops Research.

2004;**87**:167-178

2006;**51**:399-408

Maydica. 2003;**48**:221-231

*Drought Responses on Physiological Attributes of* Zea mays *in Relation to Nitrogen… DOI: http://dx.doi.org/10.5772/intechopen.93747*

[125] Göksoya AT, Demirb AO, Turana ZM, Dağüstü N. Responses of sunflower (*Helianthus annuus* L.) to full and limited irrigation at different growth stages. Field Crops Research. 2004;**87**:167-178

*Abiotic Stress in Plants*

agwat.2009.08.003

1990;**66**(4):407-415

2012;**12**(1):49-56

2004;**55**:295-306

2009;**101**:1426-1452

2012;**42**:59-67

Biology. 2014;**65**:33-67

pbi.2015. 05.004

[111] Frederick JR, Below FE, Hesketh JD. Carbohydrate, nitrogen and dry matter accumulation and partitioning of maize hybrids under drought stress. Annals of Botany.

under semi-arid climatic conditions. Agricultural Water Management. 2010;**97**:12-22. DOI: 10.1016/j.

[118] Albacete AA, Martínez-Andújar C,

[119] IPCC. Climate change. Impacts, adaptation and vulnerability. In: Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE, editors. Contribution of Working Group II to the Fourth Assessment Report of the Inter-Governmental Panel on Climate Change. Cambridge: Cambridge University Press; 2007. p. 976

[120] Harrison MT, Tardieu F, Dong Z, Messina CD, Hammer GL. Characterizing drought stress and trait influence on maize yield under current and future conditions. Global Change

Biology. 2014;**20**(3):867-878

journal.pone.0066428

Botany. 2002;**53**:13-25

2002;**17**:221-230

[121] Ray DK, Mueller ND, West PC, Foley JA. Yield trends are insufficient to double global crop production by 2050. PLoS One. 2013;**8**:e66428. DOI: 10.1371/

[122] Bruce W, Edmeades G, Barker T. Molecular and physiological approaches to maize improvement for drought tolerance. Journal of Experimental

[123] Belaygue C, Wery J, Cowan A, Tardieu F. Contribution of leaf

expansion, rate of leaf appearance, and stolon branching to growth of plant leaf area under water deficit in white clover. Crop Science. 1996;**36**(5):1240-1246

[124] Flagella Z, Rotunno T, Tarantito E, Caterina RD, Caro AD. Changes in seed yield and oil fatty acid composition of high oleic sunflower (*Helianthus annuus* L.) hybrids in relation to the sowing date and the water regime. European Journal of Agronomy.

Pérez-Alfocea F. Hormonal and metabolic regulation of source-sink relations under salinity and drought: From plant survival to crop yield stability. Biotechnology Advances. 2013. DOI: 10.1016/j.biotechadv.2013.10.005

[112] Tarighaleslami M, Zarghami R, Mashhadi M, Boojar A, Oveysi M. Effects of drought stress and different nitrogen levels on morphological traits of proline in leaf and protein of corn seed (*Zea mays* L.). American-Eurasian Journal of Agricultural & Environmental Sciences.

[113] Gallais A, Hirel B. An approach to the genetics of nitrogen use efficiency in maize. Journal of Experimental Botany.

[114] Boomsma CR, Santini JB, Tollenaar M, Vyn TJ. Maize morphophysiological responses to intense crowding and low nitrogen availability: An analysis and review. Agronomy Journal.

[115] Chapuis R, Delluc C, Debeuf R, Tardieu F, Welcker C. Resiliences to water deficit in a phenotyping platform and in the field: How related are they in maize? European Journal of Agronomy.

[116] Ruan YL. Sucrose metabolism: Gateway to diverse carbon use and sugar signaling. Annual Review of Plant

[117] Rossi M, Bermudez L, Carrari F. Crop yield: Challenges from a metabolic perspective. Current Opinion in Plant Biology. 2015;**25**:79-89. DOI: 10.1016/j.

**464**

[126] Zaidi PH, Srinivasan G, Sanchez C. Relationship between line per se and cross performance under low nitrogen fertility in tropical maize (*Zea mays* L.). Maydica. 2003;**48**:221-231

[127] Tollenaar M, Lee EA. Dissection of physiological processes underlying grain yield in maize by examining genetic improvement and heterosis. Maydica. 2006;**51**:399-408

[128] Duvick DN, Smith JCS, Cooper M. Long-term selection in a commercial hybrid maize breeding program. Plant Breeding Reviews. 2004a;**24**:109-151

[129] Lafitte HR, Edmeades GO. Association between traits in tropical maize inbred lines and their hybrids under high and low soil nitrogen. Maydica. 1994;**40**:259-267

[130] Barker T, Campos H, Cooper M, Dolan D, Edmeades GO, Habben J, et al. Improving drought tolerance in maize. Plant Breeding Reviews. 2004;**25**, in press

[131] Monneveuxi P, Sanchez C, Tiessen A. Future progress in drought tolerance in maize needs new secondary traits and cross combinations. Journal of Agricultural Science. 2008;**146**:287-300

[132] Bolaños J, Edmeades GO. Eight cycles of selection for drought tolerance in lowland tropical maize. II. Responses in reproductive behavior. Field Crops Research. 1993b;**31**:253-268

[133] Gambín BL, Borrás L, Otegui ME. Source–sink relations and kernel weight differences in maize temperate hybrids. Field Crops Research. 2006;**95**:316-326

[134] Shaw RH. Climatic requirement. In: Sprague GF, editor. Maize and Maize Improvement. Agronomy Monographs 18. Madison, WI: ASA, CSSA, and SSSA; 1977. pp. 315-341

[135] Hall AJ, Vilella F, Trapani N, Chimenti C. The effects of water stress and genotype on the dynamics of pollen-shedding and silking in maize. Field Crops Research. 1982;**5**:349-363

[136] Bolaños J, Edmeades GO. The importance of the anthesis-silking interval in breeding for drought tolerance in tropical maize. Field Crops Research. 1996;**48**:65-80. DOI: 10.1016/0378-4290(96)00036-6

[137] Lu GH, Ren DL, Wang XQ, Wu JK, Zhao MS. Evaluation on drought tolerance of maize hybrids in China. Journal of Maize Sciences. 2010;**3**:20-24

[138] Ribaut JM, Hoisington DA, Deutsch JA, Jiang C, Gonzalez de Leon D. Identification of quantitative trait loci under drought conditions in tropical maize. 1. Flowering parameters and the anthesis-silking interval. Theoretical and Applied Genetics. 1996;**92**:905-914

[139] Byrne PF, Bolaños J, Edmeades GO, Eaton DL. Gains from selection under drought versus multilocation testing in related tropical maize populations. Crop Science. 1995;**35**:63-69

[140] Tollenaar M, Wu J. Yield improvement in temperate maize is attributable to greater water stress tolerance. Crop Science. 1999;**39**:1597-1604

[141] Edmeades GO, Bolaños J, Hernandez M, Bello S. Causes for silk delay in a lowland tropical maize population. Crop Science. 1993;**33**:1029-1035

[142] Chapman SC, Edmeades GO. Selection improves drought tolerance in tropical maize populations. II. Direct and correlated responses among secondary traits. Crop Science. 1999;**39**:1315-1324

[143] Edmeades GO, Daynard TB. The relationship between final yield and photosynthesis at flowering in individual maize plants. Canadian Journal of Plant Science. 1979;**59**:585-601

[144] Westgate ME, Bassetti P. Heat and drought stress in corn: What really happens to the corn plant at pollination? In: Wilkinson D, editor. Proceedings of the 45th Annual Corn and Sorghum Research Conference; 5-6 December 1990; Chicago. Washington D.C.: ASTA; 1991. pp. 12-28

[145] Zinselmeier C, Jeong BR, Boyer JS. Starch and the control of kernel number in maize at low water potentials. Plant Physiology. 1999;**121**:25-36. DOI: 10.1104/pp.121.1.25

[146] Jacobs BC, Pearson CJ. Potential yield of maize determined by rates of growth and development of ears. Field Crops Research. 1991;**27**:281-298

[147] Reed AJ, Singletary GW, Schussler JR, Williamson DR, Christy AL. Shading effect on dry matter nitrogen partitioning, kernel number and yield of maize. Crop Science. 1988;**28**:819-825

[148] Schussler JR, Westgate ME. Assimilate flux determines kernel set at low water potential in maize. Crop Science. 1995;**35**:1074-1080

[149] Zinselmeier C, Lauer MJ, Westgate ME, Boyer JS. Reversing drought-induced losses in grain yield. Sucrose maintains embryo growth in maize. Crop Science. 1995a;**35**:1390-1400

[150] Zinselmeier C, Westgate ME, Schussler JR, Jones RJ. Low water potential disrupts carbohydrate

metabolism in maize. Plant Physiology. 1995b;**107**:385-391

[151] Zinselmeier C, Habben JE, Westgate ME, Boyer JS. Carbohydrate metabolism in setting and aborting maize ovaries. Formation in maize hybrids representing three decades of grain 1-13. In: Westgate M, Boote K, editors. Physiology and Modeling. Kernel Set in Maize. CSSA Special Publications 29. Madison, WI: CSSA; 2000

[152] Fischer KS, Palmer AFE. Tropical maize. In: Goldsworthy PR, Fisher NM, editors. The Physiology of Tropical Field Crops. Imprint: New York John Wiley & Sons Ltd., United states US Publication. 1984. pp. 213-248

[153] Tollenaar M, Dwyer LM, Stewart DW. Ear and kernel. formation in maize hybrids representing three decades of grain yield improvement in Ontario. Crop Science. 1992;**32**:432-438

[154] Singletary GW, Below FE. Growth and composition of maize kernels cultured in vitro with varying supplies of carbon and nitrogen. Plant Physiology. 1989;**89**:341-346

[155] Li Y, Wang M, Zhang F, Xu Y, Chen X, Qin X, et al. Effect of postsilking drought on nitrogen partitioning and gene expression patterns of glutamine synthetase and asparagine synthetase in two maize (*Zea mays* L.) varieties. Plant Physiology and Biochemistry. 2016;**102**:62-69. DOI: 10.1016/j.plaphy.2016.02.002

[156] Kamara AY, Kling JG, Menkir A, Ibikunle O. Agronomic performance of maize (*Zea mays* L.) breeding lines derived from a low nitrogen maize population. The Journal of Agricultural Science. 2003;**141**:221-230

**467**

**Chapter 22**

**Abstract**

fabrics.

**1. Introduction**

Ecofriendly Marigold Dye as

Natural Colourant for Fabric

This chapter highlights on the applications of marigold plant extracts as an antibacterial and antimicrobial best dyer for textiles. *Tagetes erecta* usually known as Marigold is a vital wellspring of carotenoids and lutein, developed as a nursery plant. Marigold blossoms are yellow to orange red in colour. Now a days, lutein is transforming into an unquestionably common powerful fixing, used as a part of the medicines, food industry and textile coatings. This has increased more noticeable vitality of marigold and its exceptional concealing properties. Regardless of the way that marigold blooms; its extract has been used as a measure of veterinary supports. The examination was directed to contemplate the usage of a concentrate of marigold as a trademark shading, which is antibacterial and antimicrobial. The marigold extract ability was focused on colouring of the cotton fabrics. Investigations of the dye ability, wash fastness, light fastness, antibacterial tests and antimicrobial tests can be endeavoured. Studies have exhibited that surface concealing was not impacted by washing and drying in the shadow/sunlight. These surprises reveal that the concentrate of marigold extract can be used for cotton

**Keywords:** dyeing, marigold, colour fastness, fabric, antibacterial, antimicrobial

Marigold is a common name of Tagetes species, a genus of herbs and the member of the Asteraceae family. It is a native of Mexico and other warmer parts of America and naturalised elsewhere within tropics and sub tropics. In India it is cultivated as garden plant. The flowers which are yellow to orange in colour with corymbose clusters are much used for garlands and functions and also used to

These plants do not require any additional care. They grow in all conditions of the environment. Marigold plants bare sun, heat, drought and grow in any well-drained soil. Marigolds are easy to grow even from transplants also. Marigold requires a mild climate for smooth growth and flowering. Mild climate is required during the growing period is 14.5° - 28.6°C and it improves the production of flowers at higher temperature (26.2° - 36.4°C). Depending on the climatic conditions, the marigold grows three times in a year – rainy, winter, and summer seasons. The

decorate households during celebration of festivals.

different coloured flowers are shown in **Figure 1**.

*Sujata F. Harlapur, Suneeta Harlapur* 

*and Shantabasavareddi F. Harlapur*

#### **Chapter 22**

*Abiotic Stress in Plants*

1999;**39**:1315-1324

1979;**59**:585-601

1991. pp. 12-28

10.1104/pp.121.1.25

in tropical maize populations. II. Direct and correlated responses among secondary traits. Crop Science. metabolism in maize. Plant Physiology.

[152] Fischer KS, Palmer AFE. Tropical maize. In: Goldsworthy PR, Fisher NM, editors. The Physiology of Tropical Field Crops. Imprint: New York John Wiley & Sons Ltd., United states US Publication.

Stewart DW. Ear and kernel. formation in maize hybrids representing three decades of grain yield improvement in Ontario. Crop Science. 1992;**32**:432-438

[151] Zinselmeier C, Habben JE, Westgate ME, Boyer JS. Carbohydrate metabolism in setting and aborting maize ovaries. Formation in maize hybrids representing three decades of grain 1-13. In: Westgate M, Boote K, editors. Physiology and Modeling. Kernel Set in Maize. CSSA Special Publications 29. Madison, WI: CSSA;

1995b;**107**:385-391

2000

1984. pp. 213-248

[153] Tollenaar M, Dwyer LM,

[154] Singletary GW, Below FE. Growth and composition of maize kernels cultured in vitro with varying supplies of carbon and nitrogen. Plant

Physiology. 1989;**89**:341-346

[155] Li Y, Wang M, Zhang F, Xu Y, Chen X, Qin X, et al. Effect of postsilking drought on nitrogen partitioning

and gene expression patterns of glutamine synthetase and asparagine synthetase in two maize (*Zea mays* L.) varieties. Plant Physiology and Biochemistry. 2016;**102**:62-69. DOI: 10.1016/j.plaphy.2016.02.002

[156] Kamara AY, Kling JG, Menkir A, Ibikunle O. Agronomic performance of maize (*Zea mays* L.) breeding lines derived from a low nitrogen maize population. The Journal of Agricultural

Science. 2003;**141**:221-230

[143] Edmeades GO, Daynard TB. The relationship between final yield and photosynthesis at flowering in individual maize plants.

Canadian Journal of Plant Science.

[144] Westgate ME, Bassetti P. Heat and drought stress in corn: What really happens to the corn plant at pollination? In: Wilkinson D, editor. Proceedings of the 45th Annual Corn and Sorghum Research Conference; 5-6 December 1990; Chicago. Washington D.C.: ASTA;

[145] Zinselmeier C, Jeong BR, Boyer JS. Starch and the control of kernel number in maize at low water potentials. Plant Physiology. 1999;**121**:25-36. DOI:

[146] Jacobs BC, Pearson CJ. Potential yield of maize determined by rates of growth and development of ears. Field Crops Research. 1991;**27**:281-298

Schussler JR, Williamson DR, Christy AL. Shading effect on dry matter nitrogen partitioning, kernel number and yield of maize. Crop Science. 1988;**28**:819-825

[147] Reed AJ, Singletary GW,

[148] Schussler JR, Westgate ME. Assimilate flux determines kernel set at low water potential in maize. Crop

Science. 1995;**35**:1074-1080

1995a;**35**:1390-1400

[149] Zinselmeier C, Lauer MJ, Westgate ME, Boyer JS. Reversing drought-induced losses in grain yield. Sucrose maintains embryo growth in maize. Crop Science.

[150] Zinselmeier C, Westgate ME, Schussler JR, Jones RJ. Low water potential disrupts carbohydrate

**466**
