Plant Adaptation and Phytoremediation (eBook)

Contents 5
Contributors 7
1 Toxins and Their Phytoremediation 11
1 Introduction 12
2 Toxins and Their Types 13
2.1 Salts 14
2.2 Heavy Metals 16
2.3 Herbicides and Pesticides 17
2.4 Cyanides 18
2.5 Toxic Explosives 19
3 Plant Resistance to Toxins 20
3.1 Salts 20
3.2 Heavy Metals 21
3.3 Herbicides and Pesticides 22
3.4 Cyanides 23
3.5 Toxic Explosives 24
4 Phytoremediation of Toxins 24
5 Conclusion 30
References 32
Part I Toxins and Resistance Mechanisms 43
2 Molecular Mechanisms and Genetic Basis of Heavy Metal Toxicity and Tolerance in Plants 44
1 Introduction 45
2 Heavy Metal Toxicity 46
3 Heavy Metal Tolerance 53
4 Localization and Distribution of Heavy Metals and Their Transport in the Plants 54
4.1 Amino Acids and Organic Acids 56
4.2 Phytochelatins (PCs) 57
4.3 Metallothioneins (MTs) 58
4.4 Heat Shock Proteins (HSPs) 58
4.5 Other Metal-Binding Proteins 59
5 Molecular Mechanism of Heavy Metal Accumulation in Plants 60
6 Conclusion 64
References 64
3 Biomonitoring of Heavy Metal Pollution Using Lichen (Pseudevernia furfuracea (L.) Zopf.) Exposed in Bags in a Semi-arid Region, Turkey 68
1 Introduction 69
2 Material and Methods 70
2.1 Study Area 70
2.2 Lichen Sampling and Bag Preparation 70
2.3 Sample Collection 71
2.4 Sample Preparation and Chemical Analyses 72
2.5 Results and Discussion 73
References 78
4 Heavy Metal Toxicity in Plants 80
1 Introduction 81
2 Origin and Occurrence 82
3 Mobility, Uptake and Accumulation of Heavy Metals 83
4 Mechanism of Metal Tolerance 85
5 Effect on Growth and Development 86
5.1 Germination 87
5.2 Root 87
5.3 Stem 88
5.4 Leaf 89
5.5 Dry Biomass 89
6 Effect on Plant Physiology 90
6.1 Photosynthesis 90
6.2 Water Relation 92
6.3 Essential Nutrients 93
7 Effect on Enzymes and Other Compounds 94
7.1 Root Fe(III) Reductase 95
7.2 Nitrate Reductase 95
7.3 Antioxidant Enzymes 95
8 Conclusion 96
References 97
5 Mechanism of Free Radical Scavenging and Roleof Phytohormones in Plants Under Abiotic Stresses 107
1 Introduction 108
2 ROS Production 109
3 Enzymatic Antioxidants 110
3.1 Superoxide Dismutase (SOD EC 1.15.1.1)
3.2 Catalases (EC 1.11.1.6) 111
3.3 Ascorbate Peroxidase (APX, EC 1.11.1.1) 112
3.4 Glutathione Reductase (GR, EC 1.6.4.2) 113
4 Non-enzymatic Antioxidants 113
4.1 Ascorbic Acid (Vitamin C) 113
4.2 Vitamin E (-Tocopherols) 114
4.3 Glutathione (GSH) 115
5 Phytohormones 116
5.1 Brassinosteroids (BRs) 116
5.2 Ethylene (C2H4) 117
6 Conclusion 119
7 Future Perspective 120
References 120
6 The Role of Arbuscualr Mycorrhizae in Inducing Resistance to Drought and Salinity Stress in Crops 127
1 Introduction 128
2 Arbuscular Mycorrhiza and Environmental Stresses 129
3 Arbuscular Mycorrhiza and Abiotic Stresses 130
3.1 Drought Stress 132
3.1.1 Morphological and Anatomical Effects 134
3.1.2 Metabolic Effects 134
3.1.3 Drought Resistance 134
3.1.4 Mycorrhiza and Plant Water Relations 134
3.1.5 Mycorrhiza and Soil Water Relations 137
3.1.6 Molecular Basis for Drought Resistance 137
3.2 Nutrient Stress 138
3.3 Salinity Stress 139
3.4 Heavy Metal Stress 142
4 Conclusion 143
References 143
7 Predicting Growth, Carbon Sequestration and Salinity Impacts of Forestry Plantations 150
1 Introduction 151
2 Materials and Methods 152
3 Results and Discussion 153
4 Conclusions 155
References 155
8 Structural and Functional Adaptations in Plantsfor Salinity Tolerance 157
1 Introduction 158
2 Adaptive Components of Salt Tolerance 159
2.1 Morphological Traits 161
2.2 Anatomical Traits 162
2.2.1 Succulence 168
2.2.2 Salt Excretion 168
2.3 Physiological/Biochemical Traits 169
2.3.1 Osmotic Adjustment 170
2.3.2 Ion Selectivity 170
2.3.3 Salt Exclusion 171
2.3.4 Intracellular Ion Compartmentation 171
2.3.5 Stomatal Responses 171
3 Conclusion 172
References 172
Part II Phytoremediation 177
9 Plant Resistance to Anthropogenic Toxicants: Approaches to Phytoremediation 178
1 Introduction 179
2 Environmental Contaminants 180
2.1 Toxic Heavy Metals 180
2.2 Petroleum Hydrocarbons 182
3 Mechanisms of Plant Resistance to Toxicants 184
4 Mechanisms of Uptake and Translocation of Contaminants in Plants 187
5 Phytoremediation of Polluted Soils 189
6 Conclusion 191
References 191
10 Biochemical and Molecular Aspects in Phytoremediation of Selenium 198
1 Introduction 200
2 Physiology 202
2.1 Types of Se Accumulator Plants 202
2.2 Se Toxicity and Tolerance 204
2.3 Se Uptake and Transport 210
2.4 Se Interaction with Other Salts 211
3 Biochemistry 212
3.1 Se as an Essential Element 212
3.2 Se Assimilation 213
3.3 Incorporation of Se into Protein 214
3.4 Localisation of Se Pathways 214
4 Molecular Biology 216
4.1 Sulphate Transporters 216
4.2 Genetic Code and Se Proteins 217
4.3 Key Enzyme Genes 217
4.4 Methylation and Volatilisation 220
5 Phytovolatilisation 220
5.1 Se Volatilisation 220
5.2 Variation Amongst Plants 220
5.3 Plant/Microbe Interactions 221
5.4 Environmental Factors 221
6 Phytoremediation 222
6.1 Process 222
6.2 Plant Species 222
6.3 Para-Phytoremediation 223
6.4 Problems 224
7 Conclusions/Future Directions 224
References 225
11 Perspective on Phytoremediation for Improving Heavy Metal-Contaminated Soils 232
1 Introduction 233
2 Understanding Mechanisms of Phytoremediation for Improving Heavy Metal Contaminated Soils 234
2.1 Heavy Metal Accumulation in Plants 234
2.2 Genes Involved in Heavy Metal Perception and Signal Transduction 235
2.2.1 Heavy Metal Sensors 235
2.2.2 Signaling Involved in Calcium, Reactive Oxygen Species (ROS) and Mitogen-Activated Protein Kinases (MAPK) 236
2.2.3 Phytohormone Signaling 236
2.2.4 Heavy Metal -- Induced Transcription Factors and Heavy Metal Responsive Elements 237
2.2.5 Phospholipid Signaling 238
2.2.6 Posttranscriptional Regulation of Heavy Metal-Dependent Genes By MicoRNAs 238
3 Important Standards for Heavy Metal Hyperaccumulator Plants 240
4 Biotechnology and Phytoremediation of Heavy Metal Contaminated Soils 241
5 Conclusion 245
References 246
12 The Structural and Functional Characteristics of Asiatic Desert Halophytes for Phytostabilization of Polluted Sites 250
1 Introduction 251
2 Physico-Chemical Characteristics of the Soils 253
3 Translocation and Cellular Mechanism Involved in the Phytoremediation of Trace Elements 254
4 Salt Accumulation, Silicification, and Wax Deposition Associated With Epidermal Structures of Flower 258
5 Diversity in Trichomes, Hairs and Salt Glands (SEM) 264
6 Stomatal Diversity 268
7 Conclusion 272
References 275
13 Boron and Plants 280
1 Introduction 281
2 Boron Production and Usage 282
3 Boron and Living Beings 283
4 Boron and Plants 283
4.1 Boron Tolerance, Deficiency and Toxicity in Plants 285
4.2 Boron Uptake By Plants 288
4.3 Molecular Basis of Boron Uptake and Transport 289
4.4 Boron Remobilization 291
5 Boron Pollution 292
6 Phytoremediation 296
7 Boron and Seed Germination 298
8 Boron and Genotoxicity in Plants 302
9 Conclusion 306
References 310
14 Potential for the Use of Rhizobacteria in the Sustainable Management of Contaminated Soils 317
1 Introduction 318
2 Fate of Contaminants in the Rhizosphere 320
3 The Interactions Among Bacteria and Organic and Inorganic Pollutants 321
4 Rhizospheric Microbial Populations 324
5 Methods for Assessing and Monitoring Rhizospheric Bacteria 325
6 PGPR with ACC Deaminase Activity 328
7 Plant Tolerance to Toxic Compounds and Transgenic Plants with Detoxification Genes 329
8 Strategies for Enhancing Phytoremediation 331
9 Conclusions 332
References 333
15 Phytoremediation of Saline Soils for Sustainable Agricultural Productivity 339
1 Introduction 340
2 Changes in Soil Physical Characteristics 342
3 Changes in Soil Chemical Characteristics 346
4 Removal of Salts from Soil 349
5 Improvement in Soil Fertility 352
6 Selection of Plants for Phytoremediation 353
7 Conclusion 356
References 356
16 Salts as Potential Environmental Pollutants, Their Types, Effects on Plants and Approaches for Their Phytoremediation 360
1 Introduction 361
2 Soil Salinity 361
3 Salt Types and Reasons 362
4 Effects of Soil Salinity on Plant Growth 363
4.1 Effects of Salt Stress on Cell Membranes 367
4.2 The Role of Proline Accumulation Under Salt Stress 368
5 Mechanism of Salt Tolerance 369
5.1 In Vitro Selection for Salt Tolerance 370
5.2 Mechanism of Salt Tolerance in Glycophytes and Halophytes 371
6 Phytoremediation Strategies for Overcoming Salinity Problems and Use of Halophytes as Companion Plants 373
7 Conclusion 376
References 376
17 Phytoremediation of Toxic Explosives 385
1 Introduction 386
2 Explosives as Pollutants 388
3 Phytoremediation: Detoxification of Explosives by Plants 390
4 Bacterial Genes Involved in Phytoremediation of Explosives 392
5 Transgenic Plants for Phytoremediation of Explosive Compounds 394
6 Conclusions 395
References 396
18 Phytoremediation of Cyanide 400
1 Cyanide as a Pollutant 401
1.1 Physical and Chemical Forms of Cyanide 402
1.2 Industrial and Natural Sources of Cyanide 403
1.3 Cyanide in Water and Soil 404
2 Cyanide Detoxification 405
2.1 Mechanical Processing of Cyanide Waste 405
2.2 Phytoremediation 406
2.3 Phytoremediation -- Case Studies 407
3 Uptake and Transport of Cyanide By Plants 409
3.1 Factors Affecting Uptake and Transport 411
4 Cyanide Assimilation and Metabolism 412
5 Genetic Diversity for Cyanide Assimilation in Plants 416
6 Cyanide Phytoremediation Technologies 416
7 Genomics and Proteomics of Cyanide Assimilation in Plants 417
7.1 -cyanoalanine Synthase (EC 4.4.1.9) 417
7.2 Rhodanese (EC 2.8.1.1) 418
7.3 Formamide Hydrolyase (FHL3- EC 4.2.1.66) 419
7.4 Cyanide Dihydratase (CynD) 419
8 Transgenics for Cyanide Remedy 420
9 Conclusion 421
References 421
19 Herbicides and Pesticides as Potential Pollutants: A GlobalProblem 428
1 Introduction 429
2 The Active Ingredients of Herbicides and Pesticides 430
3 Adverse Effects of Herbicides and Pesticides on Ecosystem 431
3.1 Effects on Structure and Functions of Ecosystem 431
3.2 Risks for the Species 432
3.3 Pollution Levels in Plants and Animals 433
4 Effects of Herbicides and Pesticides on Soil and Microbes 434
4.1 Structure of Soil 434
4.2 Herbicides and Pesticide Pollution on Microbial Activities 435
4.3 Persistence in Soil 436
5 Effects of Herbicides and Pesticides on Environment 437
5.1 Environmental Fate of Herbicides and Pesticides 437
5.2 Effects of Herbicides and Pesticides on Aquatic Life 438
5.3 Effects on Surface and Ground Water Quality in Agricultural Areas 439
6 Pest Resistance to Herbicides and Pesticides 440
7 Effects on Human Health 440
8 Integrated Weed Management System 442
9 Benefits vs Risks to Use Herbicides and Pesticides 443
10 Phytoremediation of Herbicides and Pesticides 444
11 Conclusion 444
References 445
Index 449