Water Stress and Crop Plants: A Sustainable Approach

By Parvaiz Ahmad

Plants are subjected to a variety of abiotic stresses such as drought, temperature, salinity, air pollution, heavy metals, UV radiations, etc. To survive under these harsh conditions plants are equipped with different resistance mechanisms which vary from species to species. Due to the environmental fluctuations agricultural and horticultural crops are often exposed to different environmental stresses leading to decreased yield and problems in the growth and development of the crops. Drought stress has been found to decrease the yield to an alarming rate of some important crops throughout the globe. During last few decades, lots of physiological and molecular works have been conducted under water stress in crop plants.

Water Stress and Crop Plants: A Sustainable Approach presents an up-to-date in-depth coverage of drought and flooding stress in plants, including the types, causes and consequences on plant growth and development. It discusses the physiobiochemical, molecular and omic approaches, and responses of crop plants towards water stress. Topics include nutritional stress, oxidative stress, hormonal regulation, transgenic approaches, mitigation of water stress, approaches to sustainability, and modern tools and techniques to alleviate the water stress on crop yields.

This practical book offers pragmatic guidance for scientists and researchers in plant biology, and agribusinesses and biotechnology companies dealing with agronomy and environment, to mitigate the negative effects of stress and improve yield under stress. The broad coverage also makes this a valuable guide enabling students to understand the physiological, biochemical, and molecular mechanisms of environmental stress in plants.

• Language: English
• Publisher: Wiley
• Release date: Jun 8, 2016
• ISBN: 9781119054467

Book preview

Table of Contents

Cover

Volume 1

Title Page

List of contributors

About the editor

Foreword

Preface

CHAPTER 1: Drought stress and photosynthesis in plants

1.1 Introduction

1.2 Effect of drought on photosynthesis in plants

1.3 Stomatal and non-stomatal limitation of photosynthesis during drought stress

1.4 Resistance of plants to drought stress

1.5 Effect of drought stress on leading plants

1.6 Conclusion and future prospects

References

CHAPTER 2: The role of crassulacean acid metabolism induction in plant adaptation to water deficit

2.1 Introduction

2.2 Adaptation of plant photosynthesis to drought stress

2.3 Crassulacean acid metabolism (CAM)

2.4 Defining the plasticity of CAM

2.5 C4-to-CAM transition

2.6 C3/CAM intermediate plants

2.7 Physiological and metabolic aspects of CAM induction by drought

2.8 CAM induction and fitness under water deficit stress

2.9 Capability of CAM to improve water-use efficiency and productivity

2.10 Conclusion and future prospects

References

CHAPTER 3: Stomatal responses to drought stress

3.1 Introduction

3.2 Stomatal status as affected by drought stress

3.3 Mechanism of stomatal closure

3.4 Responses of stomatal morphology to drought stress

3.5 Hormonal aspects of stomatal responses

3.6 Genetic aspects of stomatal responses

3.7 Effect of nutrition on stomatal responses to drought

3.8 Conclusions and future prospects

References

CHAPTER 4: Recurrent droughts: Keys for sustainable water management from case studies of tree fruit orchards in central Chile

4.1 Introduction

4.2 The concept of drought

4.3 Evolution of Chilean agriculture during the last 30 years

4.4 Technological changes in farm irrigation between 1997 and 2007 affecting the perception of drought by farmers

4.5 Government policies for securing irrigation water

4.6 Agricultural strategies to cope with droughts in future

4.7 Water management to increase efficiency

4.8 Conclusions and future prospects

References

CHAPTER 5: Global explicit profiling of water deficit-induced diminutions in agricultural crop sustainability: Key emerging trends and challenges

5.1 Introduction

5.2 Discernible detrimental effect of drought-induced down-regulation in crop sustainability at multiple scales: a general introduction

5.3 Defensive mechanisms adopted by crops at the whole plant level under specific drought scenarios: perception, sensing and acclimation

5.4 Conclusion and future prospects

References

CHAPTER 6: Sustainable agricultural practices for water quality protection

6.1 Introduction

6.2 Principal water contaminants in agricultural systems

6.3 Best practices

6.4 Conclusions and future prospects

References

CHAPTER 7: Salinity and drought stress: Similarities and differences in oxidative responsesand cellular redox regulation

7.1 Introduction

7.2 ROS production in plant cells under salt and drought stress

7.3 Antioxidative defences against salinity and drought induced oxidative stresses

7.4 Similarities and differences in ROS metabolism in plants under salt and drought stress

7.5 Drought stress and salt stress effect on plant and possible tolerance mechanisms

7.6 Redox processes that control plant growth under drought and salinity

7.7 Conclusions and future prospects

References

CHAPTER 8: Oxidative stress and plant responses to pathogens under drought conditions

8.1 Introduction

8.2 Drought stress and tolerance in plants

8.3 Effects of drought on crop plants

8.4 Effects of drought on pathogens

8.5 Pathological defence responses of crop plants under drought stress

8.6 Improvement of crop production under disease and drought conditions

8.7 Conclusions and future prospects

Acknowledgment

References

CHAPTER 9: Potential usage of antioxidants, hormones and plant extracts: An innovative approach to taming water stress limitation in crop plants

9.1 Introduction

9.2 Drought induced oxidative stress

9.3 Adaptation strategies

9.4 Application of osmoprotectants

9.5 Plant extracts as antioxidants

9.6 Conclusion and future prospects

References

CHAPTER 10: Water stress in plants: From gene to biotechnology

10.1 Introduction

10.2 Identification of genes associated with drought tolerance

10.3 Engineering drought tolerance

10.4 Conclusion and future prospects

References

CHAPTER 11: Plant aquaporin biotechnology: Challenges and prospects for abiotic stress tolerance under a changing global environment

11.1 Introduction: a short history of aquaporin research

11.2 Functional diversity of aquaporins in plants

11.3 Aquaporins structural features and functions

11.4 Functional evidence of water transport through plant aquaporin

11.5 Aquaporin gene expression studies under abiotic stresses

11.6 Genetic manipulation of aquaporin functions in transgenic plants

11.7 Conclusion and future prospects

References

CHAPTER 12: Role of proteins in alleviating drought stress in plants

12.1 Introduction

12.2 Plant adaptation to drought stress

12.3 Classification of proteins involved in drought stress response

12.4 The improvement of drought stress tolerance in plants

12.5 QTL analysis and breeding

12.6 Conclusion and future prospects

Acknowledgement

References

CHAPTER 13: Avenues for improving drought tolerance in crops by ABA regulation: Molecular and physiological basis

13.1 Introduction

13.2 Plant responses to drought stress

13.3 Role of ABA in plant stress response

13.4 Role of ABA in drought tolerance

13.5 Role of the AtNCED gene family in ABA biosynthesis

13.6 Role of AtNCED3 in response to environmental stress

13.7 ABA regulation and transport

13.8 Conclusions and future prospects

Acknowledgments

References

CHAPTER 14: MYB transcription factors for enhanced drought tolerance in plants

14.1 Introduction

14.2 Plants’ responses to stress

14.3 Molecular response to stress

14.4 Transcription factors – major players in the control of gene expression

14.5 MYB transcription factors in drought stress

14.6 Conclusions and future prospects

References

CHAPTER 15: Analysis of novel haplotype variation at TaDREB-D1 and TaCwi-D1 genes influencing drought tolerance in bread/synthetic wheat derivatives: An overview

15.1 Introduction

15.2 Wheat and environmental stresses

15.3 Physiological and phenological aspects of wheat in drought tolerance

15.4 Biochemical aspects of drought tolerance in wheat

15.5 Morphological aspects of drought tolerance

15.6 Functional analyses of drought inducible genes

15.7 DREB

15.8 Molecular markers

15.9 Conclusion and future prospects

References

CHAPTER 16: Toward integration of a systems-based approach for understanding drought stress in plants

16.1 Introduction: a brief account of effects of drought on plants

16.2 Molecular basis of drought stress tolerance in plants

16.3 The TFs: master switches with multiple roles in regulatory networks for abiotic stress tolerance

16.4 Transgenic plants harboring transcription factors versus drought stress tolerance

16.5 MicroRNAs (miRNAs) and drought stress tolerance: fact or fiction?

16.6 Systems based approach for functional genomics in plants

16.7 Conclusion and future prospects

References

CHAPTER 17: miRNA/siRNA-based approaches to enhance drought tolerance of barley and wheat under drought stress

17.1 Introduction

17.2 miRNA biogenesis and function in plants

17.3 siRNA biogenesis and function in plants

17.4 Plant drought stress

17.5 miRNAs respond to drought stress

17.6 siRNAs respond to drought stress

17.7 Drought-responsive miRNAs/siRNAs identified in wheat and barley

17.8 Strategies for functional analysis of miRNAs and siRNAs in plants

17.9 miRNA/siRNA-based approaches to enhance drought tolerance of barley and wheat under drought stress

17.10 Conclusions and future prospects

References

CHAPTER 18: MicroRNAs and their role in drought stress response in plants

18.1 Introduction

18.2 Regulation of gene expression

18.3 The effect of drought stress on physiological, biochemical, and molecular processes

18.4 microRNAs as regulator of plants development and responses to environmental stresses

18.5 Conclusion and future prospects

References

CHAPTER 19: Sugar signalling in plants: A novel mechanism for drought stress management

19.1 Introduction

19.2 Natural production and accumulation of sugars

19.3 Role of sugars: osmoregulation under drought stress

19.4 Sugars as signalling molecules

19.5 Exogenous application of sugars to alleviate the drought stress

19.6 Conclusion and future prospects

References

CHAPTER 20: Agricultural, socioeconomic, and cultural relevance of crop wild relatives, in particular, food legume landraces, in Northern Africa

20.1 Introduction

20.2 Biological nitrogen fixation and its importance for sustainable agriculture

20.3 Relevance of food legumes in Northern Africa

20.4 Food legumes of the Algerian Maghreb

20.5 Prospection, collection and taxonomy of food legumes biodiversity (plant population and rhizobacterial strains) in Northern Africa

20.6 Diversity of rhizobia nodulating peanut and response to inoculation

20.7 Challenging the legume-rhizobia symbionts with water stress and salinity under controlled conditions

20.8 Conclusion and future prospects

Acknowledgements

References

Volume 2

Title Page

List of contributors

About the editor

Foreword

Preface

CHAPTER 21: Water stress: Types, causes, and impact on plant growth and development

21.1 Introduction

21.2 Types and causes of water stress

21.3 Effect of water stress on plants

21.4 Response of plants to water stress

21.5 Conclusion and future prospects

References

CHAPTER 22: Drought stress effect on woody tree yield

22.1 Introduction

22.2 The concept of deficit irrigation

22.3 Agronomical response and water relations to deficit irrigation

22.4 Deciduous fruit trees

22.5 Perennial fruit trees

22.6 Conclusion and future prospects

References

CHAPTER 23: Drought stress effects on crop quality

23.1 Introduction

23.2 Carbohydrates

23.3 Proteins

23.4 Lipids

23.5 Mineral elements

23.6 Secondary metabolites

23.7 Conclusion and future prospects

References

CHAPTER 24: Water stress and vegetable crops

24.1 Introduction

24.2 Biotechnology and other agriculture strategies

24.3 Plant response to water stress

24.4 Water use efficiency

24.5 Irrigation

24.6 Vegetable crop cultivation and water stress

24.7 Conclusion and future prospects

References

CHAPTER 25: Water stress in grapevine (Vitis vinifera L.)

25.1 Introduction

25.2 Drought stress

25.3 Production of phytohormones

25.4 Production of specific proteins

25.5 Production of osmolytes

25.6 Regulation of ROS levels

25.7 Conclusions and future prospects

References

CHAPTER 26: Water stress and higher plants: An overview

26.1 Introduction

26.2 Molecular responses towater-deficit stress

26.3 Osmoregulatory role of compatible solutes in plants exposed to drought stress

26.4 Abscisic acid – A hormonal stress signal in plants under drought stress

26.5 Photosynthesis under drought stress: stress signal and adaptive response

26.6 Antioxidant response to drought stress

26.7 H+-Pyrophosphatase (H+-PPase) regulation as a mechanism for drought-resistance

26.8 Conclusions and future prospects

References

CHAPTER 27: Drought stress and morphophysiological responses in plants

27.1 Introduction

27.2 Drought stress in plants

27.3 Ecological factors responsible for water stress

27.4 Impact and adaptive mechanism of water stress on plants

27.5 Alteration in signaling pathway

27.6 Plant life stages and drought sensitivity

27.7 Conclusion and future prospects

References

CHAPTER 28: Water stress tolerance in maize: Perspectives and challenges

28.1 Introduction

28.2 Influence of water stress on crop growth stages in maize

28.3 Physiological basis of yield under water stress

28.4 Biochemical responses towater stress

28.5 Breeding for water stress in maize

28.6 Marker assisted selection (MAS) for water stress

28.7 Gene expression profiling to study water stress

28.8 Transgenic approaches for water stress tolerance in maize

28.9 Field phenotyping

28.10 Conclusion and future prospects

References

CHAPTER 29: Methods used for the improvement of crop productivity under water stress

29.1 Introduction

29.2 Physiological processes affected in plants under water deficit

29.3 Strategies for improving crops under water stress

29.4 Exogenous application of compatible solutes and plant growth regulators (PGRs)

29.5 Optimization of the irrigation system to increase water use efficiency

29.6 Improving plant resistance to drought

29.7 Conclusion and future prospects

References

CHAPTER 30: Wheat: Approaches to improve under water stress

30.1 Introduction

30.2 Impact of soil water deficit on some physiological traits of wheat genotypes

30.3 Effect of water stress on the activity of some carbon and malate metabolism enzymes of wheat genotypes with different drought resistance

30.4 Variations in glycine betaine accumulation and antioxidant isozymes activities in tolerant and susceptible wheat genotypes under drought stress

30.5 Screening of wheat drought reistance by SSR markers assosiated with membrane stability

30.6 Conclusion and future prospects

Acknowledgment

References

CHAPTER 31: Breeding crop plants for drought tolerance

31.1 Introduction

31.2 Drought stress and drought resistance/tolerance

31.3 Conventional/classical breeding for drought tolerance

31.4 Molecular marker assisted breeding for drought tolerance

31.5 Genetic engineering in breeding for drought tolerance

31.6 Conclusions and future prospects

References

CHAPTER 32: Mycorrhizal symbiosis: A phenomenal approach toward drought tolerance for sustainable agriculture

32.1 Introduction

32.2 Mycorrhiza: An overview

32.3 Plant-mycorrhiza interaction at the interface: the state of art

32.4 Plant under water deficiency

32.5 Mycorrhizal response to drought: avoidance versus tolerance

32.6 Role of ectomycorrhiza under drought conditions

32.7 Mechanistic insights into molecular aspect of mycorrhiza-mediated effects under drought

32.8 Conclusion and future perspectives

Acknowledgements

References

CHAPTER 33: Hormonal regulation of drought stress in plants

33.1 Introduction

33.2 Plant responses under drought stress

33.3 Phytohormonal regulation and cross-talk in various signaling pathways under drought stress

33.4 Conclusion and future prospects

References

CHAPTER 34: Brassinosteroids and drought tolerance in plants

34.1 Introduction

34.2 Response of crops todrought stress

34.3 Brassinosteroids (BRs)

34.4 Exogenous application of BRs

34.5 Conclusion and future prospects

References

CHAPTER 35: Polyamines and brassinosteroids in drought stress responses and tolerance in plants

35.1 Introduction

35.2 Role of polyamines and brassinosteroids in plant tolerance to drought stress

35.3 Application of exogenous polyamines and brassinosteroids to enhance plant tolerance to drought stress

35.4 Genetic and molecular approaches for improving plant drought tolerance

35.5 Interaction of polyamines and brassinosteroids with phytohormones and osmolytes for improving plant tolerance to drought

35.6 Recent investigations on drought stress and drought tolerance in Bulgaria and Egypt

35.7 Conclusion and future prospects

Acknowledgments

References

CHAPTER 36: Nitric oxide: A Jack of all trades for drought stress tolerance in plants

36.1 Introduction

36.2 Plant responses to drought

36.3 Drought-induced oxidative stress

36.4 Nitric oxide biosynthesis in plants

36.5 Role of nitric oxide in drought stress tolerance

36.6 Conclusion and future perspectives

References

CHAPTER 37: Plant growth under drought stress: Significance of mineral nutrients

37.1 Introduction

37.2 Macronutrients and plant growth

37.3 Micronutrients and drought stress

37.4 Conclusion and future prospects

References

CHAPTER 38: Foliar application of trace elements in alleviating drought stress

38.1 Introduction

38.2 Trace elements in soil and agriculture

38.3 Response of foliar fertilization in plants exposed to drought stress

38.4 Conclusion and future prospects

References

CHAPTER 39: Silicon as a beneficial element to combat the adverse effect of drought in agricultural crops: Capabilities and future possibilities

39.1 Introduction

39.2 Drought induced morphogenic response of plants and silicon impact

39.3 Drought induced physiological response of plants and silicon impact

39.4 Drought induced oxidative stress and silicon impact

39.5 Effect of drought in mineral distribution and silicon impact

39.6 Effect of drought in antioxidant enzymes and silicon impact

39.7 Conclusion and future prospects

References

CHAPTER 40: The interaction of drought and nutrient stress in wheat: Opportunities and limitations

40.1 Introduction

40.2 Drought stress and tolerance

40.3 Nutrient uptake and utilization, nutrient deficiencies and tolerance mechanisms

40.4 Drought by nutrient interactions and nutrient uptake under drought conditions

40.5 Opportunities and limitations of wheat improvement

40.6 Conclusion and future prospects

References

CHAPTER 41: Flooding stress and O2-shortage in plants: An overview

41.1 Introduction

41.2 How plant species can respond to flooding?

41.3 Aerenchyma and flooding stress

41.4 Seed responses under O2-shortage

41.5 Hormonal influence in flooding stress

41.6 ROS involvement under flooding stress

41.7 Conclusions and future prospects

Acknowledgements

References

Index

End User License Agreement

List of Tables

Chapter 03

Table 3.1 Stomatal conductance for the uppermost fully expanded leaves for different fertilization treatments in two types of soil, under normal and drought stress conditions (data from Graciano et al., 2005).

Chapter 04

Table 4.1 Fruit species with important increase in cultivated land from 2002 to 2012 at national level. (Adapted from ODEPA (2013) with information supplied by CIREN).

Table 4.2 Changes in cultivated land of main fruit species in the Maule region from 2007 to 2012. (Adapted from CIREN, 2013).

Table 4.3 Cherry orchards land in the Curicó province. (Elaborated with data of Fruit Cadastre CIREN-ODEPA, 2007).

Table 4.4 Irrigation systems in cherry and apple orchards in the Maule region, Chile, in 2013. (Adapted from CIREN-ODEPA, 2013).

Chapter 05

Table 5.1 Summary of drought-induced injuries at the physiological, morphological and molecular levels.

Table 5.2 Summary of drought-triggered adaptations at the physiological, morphological and molecular levels.

Chapter 06

Table 6.1 Factors affecting the erosion control effectiveness of vegetated buffer strips (slightly modified from Rickson, 2014).

Chapter 07

Table 7.1 Similar and different oxidative response under salinity and drought in different plant species.

Chapter 08

Table 8.1 Impact of major plant pathogens expected to increase in drought conditions.

Chapter 09

Table 9.1 Role of compatible osmolytes against drought stress.

Chapter 11

Table 11.1 Abiotic stress improvement using different aquaporin genes in transgenic plants.

Chapter 12

Table 12.1 List of some genes implicated in drought tolerance of different transgenic plants.

Chapter 14

Table 14.1 MYB transcription factors involved in drought stress response and tolerance.

Chapter 15

Table 15.1 Transcription factors and their functions.

Chapter 19

Table 19.1 Increase in soluble sugars in different plant species under drought stress.

Chapter 20

Table 20.1 Main morphological characteristics in seeds of Algerian cowpea landraces.

Table 20.2 Geographic location of Algerian landraces of cowpea and groundnut.

Table 20.3 Morphological descriptors used in the seed analysis of Algerian cowpea landraces.

Table 20.4 Morphological descriptors used in the seed analysis of Algerian peanut landraces.

Chapter 23

Table 23.1 Effect of water deficit (reduction of water to specific volumes during the whole crop cycle), regulated deficit irrigation (RDI, application of various volumes of water at specific times during the growing season), and partial root zone drying (PRD, application of water only to a part of the root system instead of the whole) on specific phytochemicals (Modified from Stefanelli et al., 2010).

Table 23.2 Main classes of polyphenols, according to Johnson’s (2012) classifications.

Chapter 30

Table 30.1 Soil moisture content (% of the field capacity).

Table 30.2 Effect of water stress on flag LA, DM, and LSM (LA and DM values are mean of five replications).

Table 30.3 Effect of water stress on flag leaf RWC, Chl (a + b) content and green color of flag leaf (RWC, Chl (a + b) content measured at the beginningof milk ripening, green color of flag leaf measured at the wax ripening. RWC dates represent bMean and ± SE (n = 3), leaf green color dates represent mean and ± SE (n = 30)).

Table 30.4 Correlations between different physiological parameters.

Table 30.5 Effects of a long-term soil drought on activities of CO2 metabolism enzymes in flag leaves and ear elements of various wheat genotypes.

Table 30.6 Primer nucleotide sequence used to amplify DNA.

Chapter 32

Table 32.1 Mycorrhizal effects on host-water relations during drought stress.

Chapter 33

Table 33.1 Hormonal regulation of drought stress in plants.

Chapter 35

Table 35.1 Enhanced drought tolerance in transgenic plants engineered to overproduce polyamines.

Chapter 36

Table 36.1 Drought induced oxidative stress in different plant species.

Table 36.2 Nitric oxide mediated physiological changes in plants under drought stress.

Chapter 40

Table 40.1 Regional variation in wheat area, grain yield and production (2012 data from FAOSTAT at www.faostat.fao.org, September 2014), and total fertilizer use (Heffer, 2013).

Table 40.2 Mega-environments according to the CIMMYT wheat breeding programme and important abiotic stresses (adjusted and modified from Heisey et al., 2002 and Rajaram et al., 1994). Mega-environments with widespread water and nutrient limitations are shaded in dark grey.

List of Illustrations

Chapter 02

Figure 2.1 A simplified view of crassulacean acid metabolism (CAM). Left panel: During the night, stomata open allowing atmospheric CO2 to enter the cell and is fixed by phosphoenolpyruvate carboxylase (PEPC) leading to the formation of oxaloacetate (OAA), which undergoes protonation and is stored in the vacuole as malic acid. Right panel: During the day, stomata are closed and malic acid is released from the vacuole and is decarboxylated by the malic enzyme to form CO2, which is then refixed by Rubisco and the Calvin–Benson photosynthetic carbon reduction (PCR) cycle. C3 acids are produced in the cytosol and may be stored as starch.

Figure 2.2 Changes in Δ titratable acidity during 20 days of drought treatment in S. album (a), an example of C3-CAM, and S. stoloniferum (b), an example of CAM-cycling. Values are the mean ± SD (n = 6)

Figure 2.3 Three species of Crassulaceae that exhibit C3-like pattern of gas exchange (Rosularia elymaitica and Sedum stoloniferum) and CAM-like pattern of gas exchange (Sedum album) under drought conditions.

Chapter 03

Figure 3.1 Location of stomata in plant leaf (Taiz and Zeiger, 2002), Stomata are usually most abundant on the lower surface of the leaf.

Figure 3.2 A stoma of a grass, the bulbous ends of each guard cell show their cytosolic content and are joined by the heavily thickened walls (Palevitz, 1981) (2560×).

Figure 3.3 Stomatal complexes of the sedge (Cyperus polystachyos), each complex includes two guard cells encircling a pore and two flanking subsidiary cells (Jarvis and Mansfield, 1981) (550×).

Figure 3.4 A pair of guard cells facing the stomatal cavity, toward the inside of the leaf in onion epidermis (Taiz and Zeiger, 2002) (1640×).

Figure 3.5 Sensitivity in various physiological processes to water potential. The intensity of the bar shading corresponds to the magnitude of the process. Abscisic acid is a hormone that induces stomatal closure during water stress (Taiz and Zeiger, 2002).

Figure 3.6 Water exits from the leaf through stomata. Water is pulled from the xylem to mesophyll cell walls, and then evaporates through the air spaces of the leaf. Water vapor diffuses into the leaf air, via the stomatal pore, and across the boundary layer of still air found next to the leaf surface

Figure 3.7 Relationships between midday stomatal conductance (gl) and the vapor pressure deficit of olive trees under four different levels of drought stress

Figure 3.8 Two mechanisms of stomatal closure; hydropassive (left) and hydroactive (right) pathways (adapted from Arve et al., 2011).

Figure 3.9 Density of stomatal responses (closed squares, solid lines) and stomatal index (open squares, dotted lines) to leaf water potential (wl) at 80 (a) and 90 (b) days after sowing. Correlations of stomatal size with leaf water potential at 80 (c) and 90 (d) days after sowing.

Figure 3.10 Correlations of stomatal conductance with water vapor (gs, a), net CO2 assimilation rate (An, b); and correlations of stomatal density with transpiration rate (E, c), and water use efficiency (WUE, d).

Figure 3.11 Schematic representation of abscisic acid signaling under drought stress. ABA levels were increased by environmental stimuli and lead to binding of the ABA molecule to the PYR/PYL/RCAR ABA receptor. The receptors interact with PP2C phosphatases, which are subsequently inhibited in their function of blocking downstream SnRK2/CDPK. It is distinguished that Ca²+ independent (left scheme) and Ca²+ dependent signaling (right scheme). SnRK2 proteins autophosphorylate to come to an active state and further phosphorylate downstream targets such as AREB/ABF transcription factors or ion channels subsequently leading to ABA responses such as stomatal closure in guard cells. CDPKs on the other hand are released by PYR/PYL-PP2C complex and are activated by an increase in Ca²+ concentration and further phosphorylate ion channels (Sreenivasulu et al., 2012).

Figure 3.12 Stomatal behavior in the wild type and AtERF7 RNAi lines (aterf7–1 and aterf7–3) and overexpression plants in response to abscisic acid. Stomata were opened by exposing plants for 12 h to light and high humidity, and leaves were incubated for 1.5 h in stomatal-opening solution containing 50 mM KCl, 10 mM CaCl2, and 10 mM Mes, pH 6.15. Stomatal apertures were measured 1.5 h after adding 2 mM abscisic acid. Data represent means 6 SD (n ¼ 140 to 150 stomata) (From Song et al., 2005).

Figure 3.13 (Plate 1) Sensitivity of germination to abscisic acid. Seeds from the wild type, two aterf7 RNAi lines, and two atsin3 RNAi lines were germinated and grown on MS agar medium (left side) or MS agar supplemented with 1 mM abscisic acid (right side) for 10 d

Figure 3.14 Stomatal conductance of leaves of low and high phosphorous plants during drying

Chapter 04

Figure 4.1 Map of Continental Chile and agricultural regions in this study.

Figure 4.2 Acreage of cereals and fruit trees in Chile between 1975 and 2007.

Figure 4.3 Fruit trees cultivated land by farm size in Maule region.

Figure 4.4 Irrigated land availability according to region.

Figure 4.5 Historical precipitation of the rainier months (April to October) between 1971 and 2008 in Curicó province.

Figure 4.6 Current and future water demand by region and usage.

Figure 4.7 (Plate 2) Sampled apple orchards affected by drought during the growing season 1998–1999 in the Curicó province. Basin of the Mataquito River as well as the confluence of the Teno and Lontué rivers is shown.

Figure 4.8 (Plate 3) Regional distribution of cherry orchards. Green points indicate location of cherry orchards notably concentrated around the Teno River

Figure 4.9 Annual precipitation in the Curicó province in 1998 and 2007.

Figure 4.10 Monthly measured flows of rivers Teno and Maule according to fluviometric report of DGA, season 2007–2008. (a) Teno river after La Junta, (b) Maule river at Armerillo.

Figure 4.11 Irrigated land by region.

Figure 4.12 (Plate 4) Water scarcity zones in the Maule region during drought 2007–2008.

Chapter 05

Figure 5.1 Integrated response to water deficit at whole plant level.

Figure 5.2 (Plate 5) Plants adopting morphological, physiological and molecular behaviours under drought stress.

Chapter 07

Figure 7.1 Water and salt stress tolerance mechanisms in plants

Figure 7.2 Schematic diagram showing H2O2 and peroxidases mediated possible cross-links between/among cell-wall polymers that restrict turgor driven cell´s elongation growth. A model of grass glucuronoarabinoxylans (GAXs) hemicellulosic strands (A and B) that are covalently cross-linked via diferulate (FA-FA), triferulate (FA-FA-FA) or higher order oligoferulates (FA–FA); GAX can also be covalently cross linked with lignin

Figure 7.3 A diagrammatical illustration of plant cell growth due to the influence of salinity and drought. ROS (e.g. H2O2) in presence of Fe/Cu and in scarce of cross-linkable substrates (e.g. ferulic acid or tyrosine in cell-wall matrix) favours production of OH•, which can cleave glycosidic bonds in a polysaccharide chain to loosen the plant cell-wall aiding turgor driven expansion growth of cell (A). In contrast, sufficient peroxidase and cross-linkable substrates in the presence of H2O2 favour formation of covalent cross-links (e.g. diferulate, oligoferulate and glycroprotein cross-links) that result in suppression of growth by cell wall-strengthening (B).

Chapter 08

Figure 8.1 Physiological, biochemical and molecular basis of drought responses under pathogen threat .

Figure 8.2 Behaviour of drought tolerant or halophytic pathogens under drought conditions and their effects on resistant crop plants.

Chapter 09

Figure 9.1 Schematic model for sites of reactive oxygen species (ROS) generation in various cellular parts during drought stress. The main ROS generation site is thylakoidal membranes in chloroplasts. ROS retrograde signalling (from chloroplast, mitochondria to nucleus) plays a role in stress perception, while anterograde signalling (from nucleus to chloroplast and mitochondria) plays a role in redox homeostasis to acclimatize to drought stress. Oxidative burst in other cellular sites, such as peroxisomes and apoplasts, contributed to stress perception and signal transduction. Downregulation of electron transport in chloroplasts and mitochondria contributes to redox homeostasis and stress acclimation (the explosion indicates generation of ROS sites, arrows indicate the direction of signalling).

Chapter 12

Figure 12.1 ABA-dependent and ABA-independent pathways of stress response. The first pathway regulates the expression of RD29B/RD20A and RD22 through MYC/MYB and AREB1/2 type transcription factors. ABA is mediated through Ca²+ and it is negatively regulated by ABI1/2 protein phosphatase 2C. DREB2 transcription factor is implicated in the ABA-independent pathway.

Figure 12.2 Current model of ABA receptor signaling in Arabidopsis. In the absence of ABA, the protein phosphatase keeps the kinase SnRK2 inactive by counteracting the phosphorylation of the activation loop. The presence of the ABA relieves SnRK2 from inhibition after its fixation to the proteins PYR/PYL/RCAR. Next, the activated SnRK2 phosphorylates downstream targets, including ABA-responsive transcription factors (ABF) to start transcriptional responses.

Chapter 13

Figure 13.1 (Plate 6) Biosynthesis of abscisic acid in plants. Biosynthesis is started in the plastid when carotene is converted to zeaxanthin and then violaxanthin is produced by the zeaxanthin epoxidase (ZEP). Carotenoid dioxygenase (NCED) is the key enzyme involved in the biosynthesis of ABA. The final step of ABA biosynthesis path is the oxidation of abscisic aldehyde to ABA by abscisic aldehyde oxidase (AAO). SDR, Short-chain dehydrogenase/reductase; CYP707A, Cytochrome P450, Family 707, Subfamily A (see color plate section for color details).

Figure 13.2 Signal transduction mechanism in response to ABA and abiotic stress. During abiotic stresses (e.g., drought) ABA is produced that enters the cell through ABA receptors. ABA perception and mediation of signaling is mainly based on the interaction of PYR (Pyrabactin Resistance)/regulatory component of ABA receptor (RCAR)-type ABA receptors with protein phosphatase 2Cs (PP2C) and SNF1-related protein kinase 2 (SnRK2) kinases. Both calcium (Ca²+)- dependent and Ca²+-independent pathways go on in parallel and lead to the activation of ABA related genes and some secondary messengers. In turn, plants show physiological responses that ultimately help plants to cope better with stresses, and plants exhibit normal growth and development.

Chapter 15

Figure 15.1 A puzzle showing wild relatives of wheat.

Figure 15.2 Decrease in yield of wheat affected by biotic and abiotic stresses.

Figure 15.3 Factors affecting drought stress.

Figure 15.4 Schematic diagram showing the activation of pathways for drought tolerance.

Figure 15.5 Flow chart diagram of molecular markers.

Chapter 18

Figure 18.1 Plant responses to drought and salinity through ABA-dependent and ABA-independent pathways. ABA-independent abiotic stress signaling pathway is mediated by DREB2 (dehydration responsive element binding protein) and NAC as transcription factors that activate expression of CRT/DRE (C-repeat elements/dehydration responsive element) and ERD1(EARLY RESPONSIVE TO DEHYDRATION STRESS 1), respectively. In the ABA-dependent pathways NAC, AREB/ABF (ABA-responsive element binding protein/ABRE binding factor), and MYC/MYB transcription factors are involved in the expression of ERD1, ABRE (ABA-responsive element), and MYC/MYB responsive genes, respectively.

Figure 18.2 Biogenesis pathway and function of miRNAs in plants. MIR genes are transcribed by RNA Pol II and promoted by the coactivators mediator and NOT2s. Introns are spliced by STA1 and the resulting pri-miRNAs is stabilized by DDL. The slicing of pri- and pre-miRNA is catalyzed by DCL1 and the proper slicing needs the concerted action of a set of proteins including DCL1, HYL1, SE, CPL1, CBC, DDL, SIC, TGH, and NOT2s (D-body), as well as MOS2. The sliced miRNA/miRNA* duplex is methylated by HEN1 and exported to the cytoplasm through HST or the nuclear pore. HYL1 itself or together with DCL1 loads the methylated miRNA/miRNA* duplex into AGO1, which is associated with a complex containing the chaperone HSP90 and SQN. The guide strand regulates gene expression while the passenger strand is degraded.

Figure 18.3 Auxin (IAA) signaling under optimal and stress conditions. In the absence of growth stimulating concentrations of IAA, formation of Aux-IAA::ARF dimer inhibits the expression of auxin responsive genes. In the presence of IAA, the formation of a complex consisting of IAA/TIR1 and Aux/IAA is stimulated and Aux/IAA is ubiquitinated and degraded in 26S proteasome. Subsequently, formation of ARF dimmer stimulates gene expression. miR393 downregulates TIR1; and miR160 and miR167 downregulate ARF. Under optimal growth conditions, miR393, miR160, and miR167 are upregulated and ARF-mediated gene expression is suppressed leading to diminishment of plant growth and promoting stress tolerance. ARF: auxin response factors; TIR1: Transport Inhibitor Response 1.

Figure 18.4 Involvement of miRNAs in plants drought response and tolerance as related to ABA- and auxin-signaling pathways. NFYA: nuclear transcription factor Y subunit alpha; PLD: phospholipase D, ARF: auxin response factor; TAS3: Trans-acting siRNA (small interfering RNA); TIR: Transport Inhibitor Response 1; GT: glutathione transferase; POD: peroxidase; RD22: response to dehydration 22.

Figure 18.5 Regulation of Cu/Zn SOD by miR398. Synthesis of CSD1 and CSD2 (encoding Cu/Zn SOD apoproteins) and CCS (a Cu chaperone), which incorporate Cu as a cofactor to the CSD1 and CSD2 apoproteins are negatively controlled by miR398. Under stress conditions, however, expression of miR398 is downregulated resulting in elevated levels of functional enzyme.

Figure 18.6 Involvement of miRNAs in plants drought response and tolerance as related to various physiological and molecular adaptations in plants. PDH: proline dehydrogenase; POD: peroxidase; CSD: Cu/Zn superoxide dismutase; NFYA: transcription factor Y subunit alpha; PLD: phospholipase D; ARF: auxin response factor; TIR: Transport Inhibitor Response 1; GRF: growth regulating factor; HD-Zip: homeodomain-leucine zipper; COX: cytochrome C oxidase.

Chapter 19

Figure 19.1 Synthesis of sucrose.

Figure 19.2 Important sugars and their store houses.

Chapter 20

Figure 20.1 Map showing traditional areas of the culture of cowpea in Algeria.

Figure 20.2 Geographical distribution of different ecotypes of cowpea cultivated in Algeria.

Figure 20.3 Multiple Correspondence Analysis of 122 accessions of cowpea landraces collected in Algeria.

Figure 20.4 Map of Algeria showing locations of cowpea and groundnut landraces of collections.

Figure 20.5 Dendrogram showing the distribution of strains depending on the degree of similarity of their phenotypic profiles.

Chapter 21

Figure 21.1 Effect of continued application of drought stress in leaves of C3 plants.

Chapter 23

Figure 23.1 Summary of the biosynthetic pathway and stress-induced metabolite production. The basic metabolic pathway is drawn in the circle and the effect of various biotic and abiotic stressful conditions on primary and secondary metabolites (↑: increased; ↓: decreased) are listed outside.

Chapter 24

Figure 24.1 Schematic presentation of the coupling between plant homeostasis and climate, cultivation conditions, and plant growth terms

Figure 24.2 Schematic presentation of the processes coupling soil water deficit with water stress during vegetation

Chapter 26

Figure 26.1 Water stress responses in higher plants.

Chapter 29

Figure 29.1 Neutron probe (a) and multi-sensor capacitance probe (b) to measure the soil water content and pyranometer(c) to measure the total light available.

Figure 29.2 Scheme of alternative subsurface drip irrigation.

Figure 29.3 Mulching in strawberry crops in the Central Arid Zone Research Institute, Jodhpur, Rajasthan.

Figure 29.4 Micro-dendrometers (a) and xylem sap flow sensors by heat pulse (b) and heat balance (c) used to determine the microvariations in the size of the trunk and sap flow rate, respectively.

Figure 29.5 Schematic flowchart of wireless soil moisture sensor network (Hedley et al., 2013); Wireless soil moisture sensor networks for precision irrigation scheduling. Source: Hedley (2013)

Chapter 30

Figure 30.1 (Plate 7) Gas exchange parameters (a), Net rate of photosynthesis (A). (b), Stomatal conductance (gs). (c), Intercellular CO2 concentration (Ci). (d), Transpiration rate (E) on wheat cultivars under the Heading Irrigated (T1), Heading Rainfed (T2),Grain Formation Irrigated (T3), and Grain Formation Rainfed (T4) conditions. Data are mean ±SE from five replications.

Figure 30.2 (Plate 8) Effect of drought stress on number of spikes. Data are the mean of three replications.

Figure 30.3 (Plate 9) Effect of water stress on grain yield. Data are the mean of three replications.

Figure 30.4 (Plate 10) Effects of a long-term soil drought on dynamics of the changes of CA and NAD-MDH activities in flag leaves and roots of wheat varieties, Barakatli 95 and Garagylchyg 2, during active phases of the plant development. a – CA in Barakatli 95; b – CA in Garagylchyg 2; c – NAD-MDH in Barakatli 95; d – NAD-MDH in Garagylchyg 2. 1 – control leaves; 2 – stressed leaves; 3 – control roots; 4 – stressed roots.

Figure 30.5 Dynamics of GB accumulation (μmol/g fresh weight) in leaves of wheat genotypes under soil drought conditions.

Figure 30.6 Electrophoretic spectra of superoxide dismutase (a) and effect of H2O2 on the isoenzyme composition of superoxide dismutase (b) in leaves of wheat grown under soil drought. a – watering, b – a drought; 1 – Garagylchyg 2, 2 – Gyrmyzy gul 1, 3 – Azamatli 95, 4 – Giymatli 2/17, 5 – Barakatli 95, 6 – Gyrmyzy bugda. PAGE (10% gel) was performed in a Tris-glycine buffer (pH 8.3) at 4 °C, for 3 h at a steady current of 30 mA. The amount of applied protein was 45 μg per lane of the gel.

Figure 30.7 Electrophoretic spectra of ascorbate peroxidase in leaves of wheat, grown under soil drought conditions. а – watering, b – drought; 1 – Garagylchyg 2, 2 – Gyrmyzy gul 1, 3 – Azamatli 95, 4 – Giymatli 2/17, 5 – Barakatli 95, 6 – Gyrmyzy bugda. PAGE (10% gel) was performed in a Tris-glycine buffer, pH 8.3 (with the addition of 2 mM sodium ascorbate), at 4 °C, for 3 h at a steady current of 30 mA. The amount of the applied protein was 35 μg per a lane of the gel.

Figure 30.8 Electrophoretic spectra of catalase in leaves of wheat, grown under soil drought. а – irrigation, b – drought; 1 – Garagylchyg 2, 2 – Gyrmyzy gul 1, 3 – Azamatli 95, 4 – Giymatli-2/17, 5 – Barakatli 95, 6 – Gyrmyzy bugda. Electrophoresis was performed (in 7% gel) in a Tris-glycine buffer, pH 8.3, at 4 °C, for 3 h at a steady current of 30 mA. The amount of applied protein was 40 μgs per a lane of the gel.

Figure 30.9 Electrophoretic spectra of glutathione reductase in leaves of wheat, grown under soil drought. а – watering, b – drought; 1 – Garagylchyg 2, 2 – Gyrmyzy gul 1, 3 – Azamatli 95, 4 – Giymatli 2/17, 5 – Barakatli 95, 6 – Gyrmyzy bugda. Electrophoresis was performed (in 7% gel) in a Tris-glycine buffer, pH 8.3, at 4 °C, for 3 h at a steady current of 30 mA. The amount of applied protein was 40 μg per a lane of the gel.

Figure 30.10 PCR profiles obtained with application of barc108F/barc108R primer. The arrow indicates a DNA fragment in the 156 bp dimension. M – DNA marker –100 bp. 1 – Azamatli-95, 2 - Dagdash, 3 – Qyrmyzy bugda, 4 – Zirva, 5 – Giymatli-2/17, 6 – Gobustan, 7 – Gyrmyzy gul, 8 – Pirshahin, 9 – Ruzi-84, 10 – 12thFAWWON No 97 (130/21), 11 – 44thFEFWSN No 50 (130/32), 12 – Saratovskaya, 13 – D8 №5.

Figure 30.11 PCR profiles obtained with application ofvmc89F/vmc89R primer. The arrow indicates a DNA fragment in the 173 bp dimension. M – DNA marker – 100 bp. 1 – Azamatli 95, 2- Murov, 3 – Gobustan, 4 – Gyrmyzy bugda, 5 – Bayaz, 6 – Pirshahin, 7 – Ruzi 84, 8- Saratovskaya.,9–12thFAWWON No 97 (130/21), 10 – 4thFEFWSN No 50 (130/32), 11 – FO2 N8 N4, 12 – 9thWON-SA (27 №), 13–3 RBWYT (521 №).

Figure 30.12 PCR profiles obtained with application ofwmc603F/wmc603R primer. The arrow indicates a DNA fragment in the 176 bp dimension. M – DNA marker – 100 bp. From the top: 1 – Azamatli-95, 2 – Dagdaş, 3 – Gyrmyzy bugda, 4 – Zirva, 5 – Giymatli-2/17, 6 – Gobustan, 7 – Gyrmyzy gul, 8 – Pirshahin, 9 – Ruzi-84, 10 – 12thFAWWON No 97 (130/21), 11 – 4thFEFWSN No 50 (130/32), 12 – Saratovskaya, 13 – D8 №5. 14 – FO2 N8 N4.

Chapter 31

Figure 31.1 Breeding approaches for improving drought tolerance of plants/crops.

Chapter 32

Figure 32.1 Plant root and mycorrhizal association: Types and characteristic features of mycorrhiza and their mode of colonization.

Figure 32.2 The transition from the free-living status of an EM fungus to the symbiotic phase. A growing hypha from the mycelium of T. melanosporum as observed in fluorescence microscopy is shown in (a). Hyphal morphology changes in the mantle, in which the repeated branching, characterized by incomplete transversal walls (arrowheads), originates a pseudoparenchymatous structure, as evident in the electron micrograph shown in (b). In both images, the fungal wall is falsely shaded. The transverse section of a mycorrhizal root tip stained with Trypan blue is presented in (c) showing the organization of hyphae in the mycelium, mantle and Hartig net. Bars, 10 μm.

Figure 32.3 Diagram of the two major interfaces described in mycorrhizas. (a) Intercellular interfaces (fungal wall/host wall) are found both in ecto- and endomycorrhizas. (b) Intracellular interfaces (fungal wall/interface compartment/perifungal host membrane) are typical of all endomycorrhizal associations

Figure 32.4 Schematic representation of plant root and fungal interaction at the interface. The interface is the highly dynamic cell compartment that constantly changes structure and composition based upon the mycorrhizal association and the plant partner involved as well as the stage of interaction.

Figure 32.5 Osmosensors established in yeast model. The two osmosensors Sho1p and the two component regulation component involved in the HOG pathway are known to operate during osmolarity imbalance in yeast. An SLN1 homolog complementary to sln1 mutant has also been identified in plants operating a similar mechanism to resist drought effects.

Figure 32.6 Activation of signal cascades in response to water-deficit conditions. Participation of various subcellular compartments in perception of drought by plants and translational and post translational events involving interaction between the ABA Response Element and ABA dehydration-responsive element with their specific binding proteins and coupling elements leading to abscisic acid activation to alleviate stress. Abbreviations: ABRE, ABA-response element; CE, coupling element; DRE, dehydration-responsive element; ABREBP, ABRE-binding protein; CEBP, CE-binding protein; DREBP, DRE-binding protein.

Figure 32.7 Mycorrhizal symbiosis alleviating drought stress from plants. Metabolic, biochemical, and physiological effects of fungal colonization over plant functionality both above and below ground in terms of leaf osmotic potential, stomatal conductance, transpiration rate, and scavenging activity.

Chapter 33

Figure 33.1 Different responses exhibited by plants under drought stress.

Chapter 34

Figure 34.1 Effect of drought stress on growth height of quinoa plants (Chenopodium quinoa Willd).

Figure 34.2 Effect of drought stress on leaf area of quinoa plants (Chenopodium quinoa Wild) (H1, H2, and H3: irrigation frequency after 3, 7, and 15 days).

Chapter 35

Figure 35.1 Major plant polyamines.

Figure 35.2 Major brassinosteroids.

Figure 35.3 Scheme of drought stress program and 24-epibrassinolide treatment of maize plants.

Figure 35.4 Changes in the plant height (cm), number of leaves plant−1, total leaf area plant−1 (cm²), shoot dry weight plant−1 (gm), and root dry weight plant−1 (gm) of two maize cultivars when 60-day-old plants were subjected to 0.1 mg l−1 24-epibrassinolide foliar application under different water stress treatments [well-watered (WW) (100% of field capacity), drought stress (WD1) (75% of field capacity), and drought stress (WD2) (50% of field capacity)]. Every column in each graph represents the mean (±SE) of four replicates. Asterisks indicate significant differences at the 0.05 level compared with the unsprayed plant.

Figure 35.5 Changes in the chlorophyll a, chlorophyll b, carotenoids, and total pigment content (mg g−1 FW) in leaves of two maize cultivars when 60-day-old plants were subjected to 0.1 mg l−1 24-epibrassinolide foliar application under different water stress treatments [well-watered (WW) (100% of field capacity), drought stress (WD1) (75% of field capacity), and drought stress (WD2) (50% of field capacity)]. Every column in each graph represents the mean (±SE) of four replicates. Asterisks indicate significant differences at the 0.05 level compared with the unsprayed plant.

Figure 35.6 Changes in the relative water content (%) and membrane stability index (%) in leaves of two maize cultivars when 60-day-old plants were subjected to 0.1 mg l−1 24-epibrassinolide foliar application under different water stress treatments [well-watered (WW) (100% of field capacity), drought stress (WD1) (75% of field capacity), and drought stress (WD2) (50% of field capacity)]. Every column in each graph represents the mean (±SE) of four replicates. Asterisks indicate significant differences at the 0.05 level compared with the unsprayed plant.

Figure 35.7 Scheme of PEG and Spm treatments of maize plants and sampling points.

Figure 35.8 Alteration in fresh weight, relative water content and leakage of electrolytes in shoots and roots of maize plants sprayed with 1 mM spermine and subjected to moderate (10% PEG) and severe (20% PEG) water deficit for 1 week.

Figure 35.9 Alteration in the content of chlorophyll a, chlorophyll b, carotenoids, and net photosynthesis rate of maize plants sprayed with 1 mM spermine and subjected to moderate (10% PEG) and severe (20% PEG) water deficit for 1 week.

Figure 35.10 Alteration in activity of catalase and content of free thiol-containing compounds in shoots and roots of maize plants sprayed with 1 mM spermine and subjected to moderate (10% PEG) and severe (20% PEG) water deficit for 1 week.

Chapter 36

Figure 36.1 Major effects of drought on plants.

Figure 36.2 Different mechanism of NO biosynthesis in plants.

Figure 36.3 Sites and process of NO production in a plant cell. Although several pathways have been observed in plants, some of the origins are still putative (e.g., Arg-dependent NO formation). In some cases, the origin is well known (e.g., NR).

Figure 36.4 Possible mechanisms of NO-induced oxidative stress protection.

Chapter 38

Figure 38.1 Schematic diagram of plant response to stress from deficiency and toxicity of trace elements: (a) essential trace elements; (b) non-essential trace elements .

Figure 38.2 (Plate 11) A simulation of the distribution of trace elements from aerial sources between the leaves (yellow) and roots (green) of plants .

Chapter 39

Figure 39.1 Impact of drought stress on various morphophysiological and biochemical traits of plants.

Figure 39.2 Showing the impact of silicon on drought stressed plants.

Chapter 40

Figure 40.1 (Plate 12) Development of wheat production in the last 52 years (FAOSTAT at www.faostat.fao.org, September 2014) (see color plate section for color details).

Figure 40.2 (Plate 13) Changes of nutrient uptake during development in wheat (modified from Johnston et al., 1999) (see color plate section for color details).

Figure 40.3 (Plate 14) The effect of plasticity with environment (modified from Nicotra et al., 2010) (see color plate section for color details).

Chapter 41

Figure 41.1 Scheme showing the involvement of ABA, ET and GAs in flooding adaptation. AA: Amylase Activity; CW: Cell Wall; ADH: Alcohol DeHydrogenase; PDC: Pyruvate DeCarboxylase; SK: SnorKel; SLR: SLendeR; SUB1: SUBmergence1; SnRK: Sucrose non-fermenting-1-Related protein Kinase); SUS: SUcrose Synthase.

Figure 41.2 Representative model for the O2 sensitivity under normoxia and hypoxia conditions in Arabidopsis. Under normoxia, VII ERF transcription factors (TFs) are bound to the acyl-CoA-binding proteins (ACBPs) to the membrane to avoid its movement to the nucleus. When O2 concentration decrease, VII ERFs are released from ACBPs and transported to it for activation of expression of the hyoxia response genes. When O2 levels return to normality these TFs are degraded through the N-end rule pathway: Methionine Endopeptidase (Met-APS) cleaves the methionine at the N-terminal of the VII ERFs revealing a Cystein (Cys) destabilizing residue. This C is susceptible of being chemically oxidized by O2 (Cys*). Generation of the oxidized Cys provokes the arginilation of this N-terminal by the arginyl-tRNA protein arginyltransferasa (ATE). The E3 ligase proteolysis (PRT6) recognizes this basic amino-acid terminal and targets it for proteolysis via the 26S proteasome.

Figure 41.3 Explanation of the submergence induced elongation in two lowland rice cultivars [i.e. Bomba (tall) and Senia (short)]. In both cultivars, elongation is the result of an increase of active GAs (i.e. GA1) biosynthesis due to enhanced expression of OsGA20ox1, OsGA20ox2 and OsGA3ox2 genes. In Bomba, the induced-elongation is related to increase of ET biosynthesis due to upregulation of OsACS5 gene expression. However, in Senia cultivar, submergence-induced elongation does not depend on ET, and the GA-mediated response is triggered by a still unknown mechanism, probably involving increase of acidity and/or hypoxia.

Water Stress and Crop Plants

A Sustainable Approach, Volume 1

EDITED BY

Parvaiz Ahmad

Department of Botany, S.P. College, Srinagar, Jammu and Kashmir, India

This edition first published 2016

© 2016 by John Wiley & Sons, Ltd

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Library of Congress Cataloging-in-Publication Data

Names: Ahmad, Parvaiz.

Title: Water stress and crop plants : a sustainable approach / by Parvaiz Ahmad.

Description: Chichester, West Sussex : John Wiley & Sons, Ltd., 2016– | Includes bibliographical references and index.

Identifiers: LCCN 2016009165| ISBN 9781119054368 (cloth) | ISBN 9781119054467 (epub)

Subjects: LCSH: Plants–Effect of drought on. | Plants–Drought tolerance. | Drought-tolerant plants. | Crops–Drought tolerance.

Classification: LCC QK754.7.D75 A36 2016 | DDC 581.7/54–dc23

LC record available at http://lccn.loc.gov/2016009165

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Cover image: Getty/BanksPhotos

Dedicated

to

Photo of Hakim Abdul Hameed, the founder of Jamia Hamdard, New Delhi, India.

Hakim Abdul Hameed

(1908–1999)

Founder of Jamia Hamdard

(Hamdard University)

New Delhi, India

List of contributors

Chedly Abdelly

Laboratoire des Plantes Extrêmophiles,

Centre de Biotechnologie de Borj-Cedria (CBBC), Tunisia

Fakiha Afzal

Atta-ur-Rahman School of Applied Biosciences,

National University of Sciences and Technology (NUST),

Islamabad, Pakistan

Mohammad Abass Ahanger

Stress Physiology Lab, Department of Botany,

Jiwaji University Gwalior, India

Parvaiz Ahmad

Department of Botany, S.P. College,

Srinagar, Jammu and Kashmir, India

Muhammad Asif Ahsan

Australian Centre for Plant Functional Genomics,

University of Adelaide, Urrbrae, South Australia, Australia

Muhammad Ali

Institute of Molecular Biology and Biotechnology, Bahauddin

Zakariya University, Multan and Government College

University Faisalabad, Faisalabad, Pakistan

E.F. Abd Allah

Plant Production Department, College of Food and

Agricultural Sciences, King Saud University, Riyadh,

Saudi Arabia

Galieni Angelica

Faculty of Bioscience and Technologies for Food, Agriculture

and Environment, University of Teramo, Teramo, Italy

Muhammad Shahzad Anjam

Institute of Molecular Biology and Biotechnology, Bahauddin

Zakariya University, Multan, Pakistan and Rheinische

Friedrich-Wilhelms-University of Bonn, INRES – Molecular

Phytomedicine, Bonn, Germany

Saroj Arora

Department of Botanical and Environmental Sciences,

Guru Nanak Dev University, Punjab, India

Muhammad Ashraf

Pakistan Science Foundation, Islamabad, Pakistan

Habib-ur-Rehman Athar

Institute of Pure and Applied Biology,

Bahauddin Zakariya University, Multan, Pakistan

Maurizio Badiani

Dipartimento di Agraria, Università Mediterranea

di Reggio Calabria, Reggio Calabria, Italy

Shagun Bali

Department of Botanical and Environmental Sciences,

Guru Nanak Dev University, Punjab, India

Nahidah Bashir

Institute of Pure and Applied Biology,

Bahauddin Zakariya University, Multan, Pakistan

Maali Benzarti

Laboratoire des Plantes Extrêmophiles,

Centre de Biotechnologie de Borj-Cedria (CBBC),

Tunisia

Renu Bhardwaj

Department of Botanical and Environmental Sciences,

Guru Nanak Dev University, Punjab, India

Faical Brini

Plant Protection and Improvement Laboratory,

Centre of Biotechnology of Sfax (CBS) University of Sfax,

Sfax, Tunisia

David J. Burritt

Department of Botany, University of Otago, Dunedin,

New Zealand

Devendra Kumar Chauhan

D.D. Pant Interdisciplinary Research Laboratory,

Department of Botany, University of Allahabad,

Allahabad, India

Ahmed Debez

Laboratoire des Plantes Extrêmophiles, Centre de

Biotechnologie de Borj-Cedria (CBBC), Tunisia

Murat Dikilitas

Department of Plant Protection, Faculty of Agriculture,

Harran University, S. Urfa, Turkey

Nawal Kishore Dubey

Center of Advanced Study in Botany,

Banaras Hindu University, Varanasi, India

Fabio Stagnari

Faculty of Bioscience and Technologies for Food,

Agriculture and Environment, University of Teramo, Teramo, Italy

Kaouthar Feki

Plant Protection and Improvement Laboratory,

Centre of Biotechnology of Sfax (CBS)

University of Sfax, Sfax, Tunisia

Estrella Garrido

Faculty of Agricultural Sciences and Forestry,

Universidad Católica del Maule, Curicó, Chile

Vandana Gautam

Department of Botanical and Environmental Sciences,

Guru Nanak Dev University, Punjab, India

Naima Ghalmi

Ecole Nationale Supérieure Agronomique d’Alger,

El Harrach, Algeria

Sónia Gonçalves

Centro de Biotecnologia Agrícola e Agro-Alimentar do

Alentejo (CEBAL), Beja, Portugal

Alvina Gul

Atta-ur-Rahman School of Applied Biosciences,

National University of Sciences and Technology (NUST),

Islamabad, Pakistan

Ghader Habibi

Department of Biology, Payame Noor University (PNU), Iran

Roghieh Hajiboland

Plant Science Department, University of Tabriz, Tabriz, Iran

Neha Handa

Department of Botanical and Environmental Sciences, Guru

Nanak Dev University, Punjab, India

Abeer Hashem

Botany and Microbiology Department, College of Science,

King Saud University, Riyadh, Saudi Arabia

Mohammad Anwar Hossain

Department of Genetics & Plant Breeding, Bangladesh

Agricultural University, Bangladesh

Syed Sarfraz Hussain

Australian Centre for Plant Functional Genomics,

University of Adelaide, Urrbrae, South Australia,

Australia and School of Agriculture, Food and Wine,

University of Adelaide, Urrbrae, South Australia,

Australia

Sameen Ruqia Imadi

Atta-ur-Rahman School of Applied Biosciences,

National University of Sciences and Technology,

Islamabad, Pakistan

Sumira Jan

ICAR-Central Institute of Temperate Horticulture,

Srinagar, Jammu and Kashmir, India

Tehseen Kanwal

Institute of Molecular Biology and Biotechnology,

Bahauddin Zakariya University,

Multan, Pakistan

Sema Karakas

Department of Soil Science and Plant Nutrition,

Faculty of Agriculture, Harran University,

S. Urfa, Turkey

Harpreet Kaur

Department of Botanical and Environmental Sciences,

Guru Nanak Dev University, Punjab, India

Maria Khalid

Atta-ur-Rahman School of Applied Biosciences,

National University of Sciences and Technology (NUST),

Islamabad, Pakistan

Mourad Latati

Ecole Nationale Supérieure Agronomique d’Alger,

El Harrach, Algeria

Mohamed Lazali

Ecole Nationale Supérieure Agronomique d’Alger,

El Harrach, Algeria

Hamid Manzoor

Institute of Molecular Biology and Biotechnology,

Bahauddin Zakariya University,

Multan, Pakistan

Seema Mahmood

Institute of Pure and Applied Biology,

Bahauddin Zakariya University,

Multan, Pakistan

Pisante Michele

Faculty of Bioscience and Technologies for Food,

Agriculture and Environment, University of Teramo,

Teramo, Italy

Enrique Misle

Faculty of Agricultural Sciences and Forestry,

Universidad Católica del Maule, Curicó, Chile

Narghes Morad-Talab

Plant Science Department, University of Tabriz, Tabriz, Iran

Sibgha Noreen

Institute of Pure and Applied Biology,

Bahauddin Zakariya University, Multan, Pakistan

Puja Ohri

Department of Zoology, Guru Nanak Dev University,

Punjab, India

Ghania Ounane

Ecole Nationale Supérieure Agronomique d’Alger,

El Harrach, Algeria

Sidi Mohamed Ounane

Ecole Nationale Supérieure Agronomique d’Alger,

El Harrach, Algeria

Hassan Pakniyat

Crop Production and Plant Breeding Department,

College of Agriculture, Shiraz University, Shiraz, Iran

Mohammad Pessarakli

School of Plant Sciences, The University of Arizona,

Tuscan, Arizona, USA

Hadi Pirasteh-Anosheh

National Salinity Research Center, Yazd, Iran

Poonam

Department of Botanical and Environmental Sciences,

Guru Nanak Dev University, Punjab, India

Muhammad Kamran Qureshi

Department of Plant Breeding and Genetics,

Bahauddin Zakariya University, Multan, Pakistan

Bushra Rashid

National Centre of Excellence in Molecular Biology,

Thokar Niaz Baig University of the Punjab, Lahore, Pakistan

Sumaira Rasul

Institute of Molecular Biology and Biotechnology,

Bahauddin Zakariya University, Multan, Pakistan

Amandeep Rattan

Department of Botanical and Environmental Sciences,

Guru Nanak Dev University, Punjab, India

Kilani Ben Rejeb

Laboratoire des Plantes Extrêmophiles,

Centre de Biotechnologie de Borj-Cedria (CBBC),

Tunisia and Adaptation des Plantes aux Contraintes

Environnementales, Université Pierre et Marie Curie

(UPMC), Paris, France

Armin Saed-Moucheshi

Crop Production and Plant Breeding Department,

College of Agriculture, Shiraz University, Shiraz, Iran

Arnould Savouré

Adaptation des Plantes aux Contraintes Environnementales,

Université Pierre et Marie Curie (UPMC), Paris, France

Anket Sharma

Department of Botanical and Environmental Sciences,

Guru Nanak Dev University, Punjab, India

Bu-Jun Shi

Australian Centre for Plant Functional Genomics,

University of Adelaide, Urrbrae, South Australia,

Australia and School of Agriculture, Food and Wine,

University of Adelaide, Urrbrae, South Australia, Australia

Zoya Siddique

Atta-ur-Rahman School of Applied Biosciences, National

University of Sciences and Technology, Islamabad, Pakistan

Shweta Singh

D.D. Pant Interdisciplinary Research Laboratory,

Department of Botany, University of Allahabad,

Allahabad, India

Geetika Sirhindi

Department of Botany, Punjabi University, Punjab, India

Agostino Sorgonà

Dipartimento di Agraria, Università Mediterranea di Reggio

Calabria, Reggio Calabria, Italy

Pradeep Sornaraj

Australian Centre for Plant Functional Genomics,

University of Adelaide, Urrbrae, South Australia, Australia

Sihem Tellah

Ecole Nationale Supérieure Agronomique d’Alger,

El Harrach, Algeria

Ashwani Kumar Thukral

Department of Botanical and Environmental Sciences,

Guru Nanak Dev University, Punjab, India

Durgesh Kumar Tripathi

Center of Advanced Study in Botany,

Banaras Hindu University, Varanasi, India

Mohammad Nesar Uddin

Department of Crop Botany, Bangladesh Agricultural

University, Bangladesh

Zafar Ullah Zafar

Institute of Pure and Applied Biology, Bahauddin Zakariya

University, Multan, Pakistan

About the editor

Dr. Parvaiz Ahmad is Senior Assistant Professor in Department of Botany at Sri Pratap College, Srinagar, Jammu and Kashmir, India. He completed his postgraduation in Botany in 2000 from Jamia Hamdard, New Delhi, India. After receiving a Doctorate degree from the Indian Institute of Technology (IIT), Delhi, India, he joined the International Centre for Genetic Engineering and Biotechnology, New Delhi, in 2007. His main research area is Stress Physiology and Molecular Biology. He has published more than 40 research papers in peer-reviewed journals and 35 book chapters. He is also an Editor of 14 volumes (1 with Studium Press Pvt. India Ltd., New Delhi, India, 9 with Springer, New York, 3 with Elsevier USA, and 1 with John Wiley & Sons, Ltd). He is a recipient of the Junior Research Fellowship and Senior Research Fellowship by CSIR, New Delhi, India. Dr. Parvaiz has been awarded the Young Scientist Award under Fast Track scheme in 2007 by the Department of Science and Technology (DST), Govt. of India. Dr. Parvaiz is actively engaged in studying the molecular and physiobiochemical responses of different agricultural and horticultural plants under environmental stress.

Foreword

Humans started their community life nearly 10,000 years back by beginning to gather and cultivate plants and domesticate animals. In this way the foundations for agriculture were laid as an important part of life. A great development has taken place since then, but still a large population is suffering from hunger in different countries. Land degradation is leading to tremendous soil losses and different types of stresses are posing great threat to the soil productivity, which in turn is affecting plant growth and development ending up with decreases in the crop yields.

On the other hand, demographic developments are posing another threat and attempts are to be made to combat this grave situation in order to feed the hungry. Plant scientists are trying hard to develop plants with higher yields and those which can be grown on marginal lands. They are working hard to develop techniques with latest technologies to understand the molecular, physiological, and biochemical pathways in order to meet the global agricultural needs by overcoming the stresses affecting the yield.

Water is the most critical resource for a sustainable agricultutal development in the world. It is a must for the agriculture as an important part of our environment. The problems arising from under and overirrigation emphasize the fact that humans cannot continue with the current use and throw away policy with their natural resources; in particular, regarding water. The area of irrigated lands is reaching a level of nearly 500 million ha and approximately 20% of these irrigated lands provide only 50% of the global food supply. Expectations are that the need for irrigation water will increase far more by 2025. Water scarcity will cause stress problems in plants. In view of this we have to look for the possibilities to overcome water shortages in the agriculture so as to increase the water use efficiency, use marginal lands, mariginal waters, and techniques to overcome stress problems in plants to feed hungry mouths.

This volume is therefore a compilation of different perspectives from around the globe that directly or indirectly lead us to understand the mechanism of plant stress tolerance and mitigation of these dangerous stresses through sustainable methods.

Chapter 1 deals with the drought stress and photosynthesis in plants. Here, the authors give details regarding the effect of drought on photosynthesis in plants, stomatal and non-stomatal limitation of photosynthesis during drought stress, resistance of plants to drought stress, and effect of drought stress on leading plants.

Chapter 2 discusses the role of crassulacean acid metabolism induction in plants as an adaptation to water deficit; physiological and metabolic aspects of CAM induction by drought, CAM induction and fitness under water deficit; capability of CAM to improve water-use efficiency, and productivity is also explained clearly.

In Chapter 3 authors enlighten the effect of drought stress on the functioning of stomata, and hormonal, nutritional, as well as genetic aspects under drought stress.

Chapter 4 discusses the case study under the heading of recurrent droughts with details about keys for sustainable water management from case studies of tree fruit orchards in central Chile.

In Chapter 5, global explicit profiling of water deficit-induced diminutions in agricultural crop sustainability is given as a key emerging trend and challenge; defensive mechanisms adopted by crops at whole plant level under specific drought scenarios: perception, sensing, and acclimation is also explained.

The information on sustainable agricultural practices for water quality protection are discussed at length in Chapter 6.

In Chapter 7, salinity and