**3. Salt stress**

Salinity stress is one of the most serious abiotic stress factors. It causes morphological, biochemical, cytogenetic, and molecular changes in plants [9, 76, 77, 78]. Root lengths, shoot lengths, and root numbers decrease in plants exposed to salt stress [7]. Moreover, salinity also induces oxidative stress in plants due to production ROS [79, 80]. These ROS are produced in the cell and interacted with a number of vital cellular molecules and metabolites, thereby leading to a number of destructive processes causing cellular damage [81].

BRs reduce impacts of salt stress on ROS, gene expression, mitotic index, nutrient uptake, and growth [9, 82, 83–88]. There are lots of studies to analyse alleviation of salt stress by using BRs. In these studies, different parameters have been investigated to understand the mechanism of BRs on salt stress (Table 1).


#### Abiotic Stress Alleviation with Brassinosteroids in Plant Roots http://dx.doi.org/10.5772/61336 377


concluded that water stress negatively influenced nodulated root, but BRs increased tolerance

Several researchers have found that increased proline levels can protect plants from water stress. BR treatment increased the contents of proline and protein under water stress [68]. Zhang et al. [69] also indicated that BR treatment promoted the accumulation of osmoprotec‐ tants, such as soluble sugars and proline. It may be due to the fact that BRs activated the enzymes of proline biosynthesis, which caused an additive effect on the proline content [70].

Drought stress causes increment in H2O2 due to decrease in antioxidative enzyme activities [71]. Plants have improved various defense mechanisms to respond and adapt to water stress [72]. Vardhini et al. [73] studied with sorghum seedlings grown under PEG-imposed water stress and investigated the effects of HBL and 24-epiBL on the activities of four oxidizing enzymes: superoxide dismutase (SOD), glutathione reductase (GR), IAA oxidase, and poly‐ phenol oxidase (PPO). They found that supplementation of both the BRs resulted in enhanced SOD and GR but lowered IAA oxidase and PPO. Li and Feng [68] also reported that treatment of brassinolide significantly increased peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) activities of seedlings under normal water and mild water stress. Therefore, increment in enzyme activities provided tolerance of *Xanthoceras sorbifolia* seedlings to drought stress. It has been found that BRs can induce the expression of some antioxidant genes and enhance the activities of antioxidant enzymes such as SOD, POD, CAT, and APX [74, 75].

Salinity stress is one of the most serious abiotic stress factors. It causes morphological, biochemical, cytogenetic, and molecular changes in plants [9, 76, 77, 78]. Root lengths, shoot lengths, and root numbers decrease in plants exposed to salt stress [7]. Moreover, salinity also induces oxidative stress in plants due to production ROS [79, 80]. These ROS are produced in the cell and interacted with a number of vital cellular molecules and metabolites, thereby

BRs reduce impacts of salt stress on ROS, gene expression, mitotic index, nutrient uptake, and growth [9, 82, 83–88]. There are lots of studies to analyse alleviation of salt stress by using BRs. In these studies, different parameters have been investigated to understand the mechanism of

**References** [9] [84] [85] [86] [87] [88]

Increased *Cu/Zn-SOD, APX, CAT, GR* and *OsBRI* expressions


leading to a number of destructive processes causing cellular damage [81].

**gene expression** --- --- --- ---

to water stress and EBL was relatively more effective than HBL.

376 Abiotic and Biotic Stress in Plants - Recent Advances and Future Perspectives

**3. Salt stress**

BRs on salt stress (Table 1).

**Effects on**

**Table 1.** Effects of BRs on plants subjected to salt stress Dashes indicate that there are no results in study.
