Preface

Plants are subjected to numerous environmental stresses, which can be classified into two broad areas: abiotic and biotic stresses. While the first is considered the damage done to an organism by other living organisms, the latter occurs as a result of a negative impact of non-living factors on the organisms. In this scenario, the current most accepted opinion of scientists is that both biotic and abiotic factors in nature and agroecosystems are affected by climate change, which may lead to significant crop yield decreases worldwide. We should take into consideration not only this environmental concern but also the fact that 20 years from now the earth's population will need 55% more food than it can produce now. Therefore, it is crucial to address such concerns and bring about possible solutions to future plant stressrelated outcomes that might affect global agriculture.

Facing the increasing population, and consequently higher demand for food, fiber, and biofuels, the demand for agricultural products is set to increase in the next few years. Thus, plant science research to improve sustainable production worldwide is the vital task of the scientific community to address the increasing demands and needs for such products. In the last few decades, the results of wide-scale research have been applied, field mechanization improved, technical and agricultural methods developed, research and training extended, and new methods established worldwide.

This book intends to provide the reader with a comprehensive overview of both biotic and abiotic stresses through 10 chapters that include case studies and literature reviews about these topics. Hence, this volume presents outstanding chapters involving theoretical and practical research work carried out by experienced researchers. There will be a particular focus on understanding the physiological, biochemical, and molecular changes observed in stressed plants as well as the mechanisms underlying stress tolerance in plants.

Taking into consideration the fact that environmental vulnerabilities are the significant constraints for growth, development, and productivity of crops, this book is a must-read work for academic students, scientists, and enthusiasts about this theme. The methods and technologies recommended here have resulted in essential highlights about how to tackle abiotic/biotic stress in plants, achieve higher yields, and maximize the use of inputs under harmful environmental conditions. In other words, this is a valuable resource about biotic and biotic factors that affect crops' yields, particularly for those who work in research organizations and higher academic institutions. This textbook is a precise and complete work that will benefit graduates, postgraduates, and researchers who work with environmental stressors in plants.

As editor, I am grateful to all the authors who have written their chapters meticulously and contributed their valuable work to this book. I would also like to thank the editorial staff of IntechOpen Publisher and its team for all the kind support provided throughout the whole editorship process, enabling this book to be produced on time and in an excellent manner. I express my special thanks to my mother

**II**

**Chapter 7 99**

**Chapter 8 109**

**Chapter 9 129**

**Chapter 10 139**

Superoxide Dismutase: A Stable Biochemical Marker for Abiotic Stress

Melatonin: Role in Increasing Plant Tolerance in Abiotic Stress Conditions *by Raziye Kul, Aslıhan Esringü, Esin Dadasoglu, Üstün Sahin, Metin Turan,* 

Regulation Effect of Different Water Supply to the Nitrogen and Carbon

Chickpea Abiotic Stresses: Combating Drought, Heat and Cold *by Peter Kaloki, Viola Devasirvatham and Daniel K.Y. Tan*

*Selda Örs, Melek Ekinci, Guleray Agar and Ertan Yildirim*

*by Szilvia Veres, László Zsombik and Csaba Juhász*

Tolerance in Higher Plants

Metabolism

*by Mukesh K. Berwal and Chet Ram*

Francisca, my wife Maria, and my kids Matheus and Giovana, for inspiring me and being my pillars of strength. Last but not least, my deepest gratitude is for my Lord and Savior, Jesus Christ, who takes care of me and gives me health to make my dreams come true. "I will give thanks to you, LORD, with all my heart; I will tell of all your wonderful deeds." Ps. 9:1.

#### **Alexandre Bosco de Oliveira**

Professor of Agriculture, Plant Science Department, Federal University of Ceará, Fortaleza, Ceará, Brazil

**1**

Section 1

Multiple Stresses

Section 1 Multiple Stresses

**3**

**Chapter 1**

Plants

**Abstract**

Biotic and Abiotic Stresses in

*Audil Gull, Ajaz Ahmad Lone and Noor Ul Islam Wani*

an appropriate biochemical and physiological response.

cellular response and signaling

**1. Introduction**

**Keywords:** environmental stresses, temperature, radiation, bacteria, fungi,

Stress in plants refers to external conditions that adversely affect growth, development or productivity of plants [1]. Stresses trigger a wide range of plant responses like altered gene expression, cellular metabolism, changes in growth rates, crop yields, etc. A plant stress usually reflects some sudden changes in environmental condition. However in stress tolerant plant species, exposure to a particular stress leads to acclimation to that specific stress in a time time-dependent manner [1]. Plant stress can be divided into two primary categories namely abiotic stress and biotic stress. Abiotic stress imposed on plants by environment may be either physical or chemical, while as biotic stress exposed to the crop plants is a biological unit like diseases, insects, etc. [1]. Some stresses to the plants injured them as such that plants exhibit several metabolic dysfunctions [1]. The plants can be recovered from injuries if the stress is mild or of short term as the effect is temporary while as severe stresses leads to death of crop plants by preventing flowering, seed formation and induce senescence [1]. Such plants will be considered

Plants are subjected to a wide range of environmental stresses which reduces and limits the productivity of agricultural crops. Two types of environmental stresses are encountered to plants which can be categorized as (1) Abiotic stress and (2) Biotic stress. The abiotic stress causes the loss of major crop plants worldwide and includes radiation, salinity, floods, drought, extremes in temperature, heavy metals, etc. On the other hand, attacks by various pathogens such as fungi, bacteria, oomycetes, nematodes and herbivores are included in biotic stresses. As plants are sessile in nature, they have no choice to escape from these environmental cues. Plants have developed various mechanisms in order to overcome these threats of biotic and abiotic stresses. They sense the external stress environment, get stimulated and then generate appropriate cellular responses. They do this by stimuli received from the sensors located on the cell surface or cytoplasm and transferred to the transcriptional machinery situated in the nucleus, with the help of various signal transduction pathways. This leads to differential transcriptional changes making the plant tolerant against the stress. The signaling pathways act as a connecting link and play an important role between sensing the stress environment and generating

#### **Chapter 1**
