Waterlogging Signalling and Tolerance in Plants (eBook)

Preface 5
Contents 8
Chapter 1: Oxygen Transport in Waterlogged Plants 19
Introduction 20
O2 Transport in Plants: Some Basic Physics, and Modelling of O2 Diffusion 21
A Survey of Methods to Study O2 Transport and Related Parameters in Higher Plants 23
Anatomical Adaptations to Flooding Stress: Barriers to Radial Oxygen Loss 26
Anatomical Adaptations to Flooding Stress: Formation of Aerenchyma 27
Mechanisms of O2 Transport in Plants 29
O2 Transport in Plants: Ecological Implications 34
Open Questions and Directions of Further Research 34
References 35
Chapter 2: Waterlogging and Plant Nutrient Uptake 39
Introduction 39
Effects of Hypoxia on Nutrient Uptake 42
Physiological Effects of Hypoxia Change Root Elongation Rate, k, and Maximal Nutrient Uptake Rate, Imax 42
Waterlogging Leads to Changes in the Availability, Cli, and the Effective Diffusion Coefficient, De, of Some of the Nutrients 44
In Waterlogged Conditions, Some Plant Species Show More Root Hair Development, Longer and Thinner Roots and Increased Levels o 45
Waterlogging Decrease Evaporation and Bulk Water Flow, Vo 46
In Response to Waterlogging the Kinetics of Root Transport Systems, km and Imax, Can Be Modified 47
Summary and Concluding Remarks 47
References 48
Chapter 3: Strategies for Adaptation to Waterlogging and Hypoxia in Nitrogen Fixing Nodules of Legumes 52
Introduction: The Oxygen Diffusion BarrierOxygen Diffusion Barrier in Nodules 53
Nodule Morphology and the Gas Diffusion Barrier 53
Modulation of the Gas Diffusion Barrier 55
Control of the Gas Diffusion Barrier in Response to Sub-Ambient O2 and Flooding 55
Mechanism of Regulation of the Gas Diffusion Barrier in Response to pO2 56
Developmental and Morphological Adaptations of Nitrogen-Fixing Nodules to Low Oxygen Stress 58
Secondary AerenchymaSecondary Aerenchyma Formation 58
The Inner CortexInner Cortex and Infected ZoneInfected Zone 59
Influence of Adaptive Changes on Nitrogen Fixation Under Altered Rhizosphere pO2 Conditions 60
Strategies of Adaptation: Flood-Tolerant Legumes and Oxygen Diffusion 61
Tropical Wetland Legumeswetland legumes 61
Nodulation of Submerged Stems and Roots: Increased Porosity Mechanisms 62
Aerial Nodulation of Stems and Adventitious Roots: Avoidance Mechanisms 63
Lotus uliginosus: A Temperate Wetland Legume 64
Strategies of Adaptation: Alternate Nodulationnodulation Pathways for Flooding Tolerant Legumes 65
Intercellular-Based Mechanism of Nodulation: The Lateral Root Boundary Pathway 65
Sesbania rostrata: A Model Legume for Aquatic Nodulation 66
Summary and Concluding Remarks 68
References 70
Chapter 4: Oxygen Transport in the Sapwood of Trees 75
Brief Anatomy of a Woody Stem 76
Atmosphere Inside a Stem: Gas Composition and its Effects on Respiration 77
Gas Transport and Diffusion 80
Radial and Axial Oxygen Transport to Sapwood 82
Sapwood Respiration 84
References 87
Chapter 5: pH Signaling During Anoxia 91
Introduction 91
pH, Signal and Regulator 93
pH as Systemic Signal 94
The Nature of pH Transmission 95
What is the Information? 95
Anoxic Energy Crisis and pH Regulation 97
The Davis-Roberts-Hypothesis: Aspects of pH Signaling 97
Cytoplasmic Acidification, ATP and Membrane Potential 98
Cytoplasmic pH (Change), An Error Signal? 99
pH Interactions Between the (Major) Compartments During Anoxia 100
The pH Trans-Tonoplast pH Gradient 100
Cytoplasm and Apoplast 102
The Apoplast Under Anoxia 102
Anoxia Tolerance and pH 103
pH as a Stress Signal - Avoidance of Cytoplasmic Acidosis 104
pH as Signal for Gene Activation 105
pH Signaling and Oxygen Sensing 106
Conclusions 106
References 107
Chapter 6: Programmed Cell Death and Aerenchyma Formation Under Hypoxia 111
Introduction 112
Description of Aerenchyma Formation: Induced and Constitutive 114
Evidence for PCD During Lysigenous Aerenchyma Formation 115
Description of the Sequence of Events Leading to Induced Lysigenous Aerenchymalysigenous aerenchyma Formation 116
Stimuli for Lysigenous Aerenchyma Development (Low Oxygen, Cytosolic Free Calciumfree calcium, Ethyleneethylene, P, N, and S S 117
Oxygen Deprivation 117
Free Cytoplasmic Calcium 118
Ethylene 119
P, N, and S Starvation 120
Energy and Redox Status of the Cell 120
PCD and the Clearing of the Cell Debris 122
Cellular Degrading Enzyme Activities 123
Sequence of Events Leading to Lysigenous Cavity Formation 124
What Determines the Architecture of Aerenchyma? - Targeting and Restricting PCD 124
Future Prospects 125
References 125
Chapter 7: Oxygen Deprivation, Metabolic Adaptations and Oxidative Stress 131
Introduction 132
Anoxia: Metabolic Events Relevant for ROS Formation 133
``Classic´´ Metabolic Changes Under Oxygen Deprivation Related to ROS Formation 133
Changes in Lipid Composition and Role of Free Fatty Acids Under Stress 136
Modification of Lipids: LPlipid peroxidation 137
ROS and RNS Chemistry Overview and Sources of Formation Under Lack of Oxygen 138
Reactive Oxygen Species 138
Reactive Nitrogen SpeciesReactive nitrogen species 139
Plant Mitochondria as ROS Producers: Relevance for Oxygen Deprivation Stress 141
O2 Fluxes in Tissues and Factors Affecting O2 Concentration In Vivo 143
Microarray Experiments in the Study of Hypoxia-Associated Oxidative Stress 144
Update on Antioxidant Protection 145
Low Molecular Weight Antioxidants 146
GlutathioneGlutathione 146
Ascorbic acidAscorbic acid 146
Tocopherol (Vitamin E)Tocopherol (Vitamin E) 147
Phenolic CompoundsPhenolic compounds as Antioxidants 148
Enzymes Participating in Quenching ROS 148
Superoxide Dismutase 148
CatalasesCatalases, Peroxidasesperoxidases and Ascorbate Peroxidasesascorbate peroxidases 149
Phospholipid Hydroperoxide Glutathione PeroxidasePhospholipid hydroperoxide glutathione peroxidase 150
Concluding Remarks 150
References 151
Chapter 8: Root Water Transport Under Waterlogged Conditions and the Roles of Aquaporins 161
Introduction 161
Variable Root Hydraulic Conductance (Lr) 162
Changes in Root Morphology and Anatomy 163
Root Death and Adventitious Roots 163
Barriers to Radial Flow 164
Varying the Root or Root Region Involved in Water Uptake 167
Volatile and Toxic Compounds in Anaerobic Soils 168
Water Permeability of Root Cells and Aquaporins 168
Plant Aquaporins 169
Responses at the Cell Level Affecting Water Permeability and Potential Mechanisms 171
Changes in Water Potential 172
Decreased ATP, Implications for Transport and Interactions with Aquaporins 172
Decrease in Cytosolic pH 175
Increase in Cytosolic Free Ca2+ 178
Increase in ROS 178
Other Changes Under Oxygen Deficiency that Could Affect Water Transport 179
Transport of Other Molecules Besides Water Through MIPs Relevant to Flooding 180
Signalling 181
Conclusion and Future Perspectives 182
References 183
Chapter 9: Root Oxygen Deprivation and Leaf Biochemistry in Trees 191
Introduction 192
Root O2 Deprivation 193
Root O2 Deprivation: Effects on Leaves 195
The Role of ADH 195
Carbon Recovery 196
Differential mRNA Translation 198
Effects on Cell Metabolism 199
Conclusions 201
References 202
Chapter 10: Membrane Transporters and Waterlogging Tolerance 206
Introduction 207
Waterlogging and Plant Nutrient Acquisition 207
Root Ion Uptake 207
Transport Between Roots and Shoots 208
Ionic Mechanisms Mediating Xylem Loading 209
Control of Xylem Ion Loading Under Hypoxia 210
Oxygen Sensing in Mammalian Systems 210
Diversity and Functions of Ion Channels as Oxygen Sensorsoxygen sensors 210
Mechanisms of Hypoxic Channel Inhibition 212
The Molecular Mechanisms of Oxygen Sensing in Plant Systems Remain Elusive 212
Impact of Anoxia and Hypoxia on Membrane Transport Activity in Plant Cells 213
Oxygen Deficiency and Cell Energycell energy Balance 213
H+ and Ca2+ Pumps 213
Ca2+-Permeable Channels 214
K+-Permeable Channels 215
Secondary Metabolites Toxicity and Membrane Transport Activity in Plant Cells 215
Waterlogging and Production of Secondary Metabolitessecondary metabolites 215
Secondary Metabolite Production and Plant Nutrient Acquisition 216
Secondary Metabolites and Activity of Key Membrane Transporters 217
Pumps 217
Carriers 218
Channels 218
Breeding for Waterlogging Tolerance by Targeting Key Membrane Transporters 220
General Trends in Breeding Plants for Waterlogging Tolerance 220
Improving Membrane TransportersXe 220
Chapter 11: Ion Transport in Aquatic Plants 229
Introduction 229
Morphological and Physiological Adaptations of Aquatic Plants 230
Ion Transport 232
Cation Transport Systems 236
Anion Transport Systems 238
Root Versus Leaf Uptake 238
Molecular Characterisation of Transporter Genes 240
The Relevance of Aquatic Plants to Terrestrial Plants in Regards to Waterlogging and Inundation Stresses 241
Conclusions 241
References 242
Chapter 12: Genetic variabilityGenetic Variability and Determinism of Adaptation of Plants to Soil water-loggingWaterlogging 248
Introduction 249
Diversity Among PopulationsXe 253
Genetic Control of Traits Related to hypoxiaHypoxia Tolerance 256
Genetic Determinism of Tolerance to water-loggingWaterlogging and Identification of the Involved Genome Regions 257
Methodology of the Detection of QTLQTLQTL for hypoxiaHypoxia Tolerance: Caution and Strategies 258
SubmergenceSubmergence Tolerance and water-loggingWaterlogging Tolerance 258
QTLQTLQTL Detection for Constitutive Traits of Tolerance 262
Comparison with a Control Environment 262
Major QTLlociLoci Detected for hypoxiaHypoxia Tolerance 263
QTLQTLQTL for Traits Submitted to Natural Selection Pressure in Hypoxic Environments 263
QTLQTLQTL Detection for Breeding Purposes 264
QTLQTLQTL Detection for Tolerance to hypoxiaHypoxia 264
Conclusions 267
References 267
Chapter 13: Improvement of Plant Waterlogging Tolerance 273
Introduction 273
Genetic ResourcesGenetic resources of the Tolerance 274
Selection CriteriaSelection criteria 277
Genetic StudiesGenetic studies on Waterlogging Tolerance 279
Marker-Assisted SelectionMarker assisted selection 281
QTLQTL Controlling Waterlogging Tolerance 281
Accurate Phenotypingphenotyping is Crucial in Identifying QTLs for Waterlogging Tolerance 284
References 287
Index 292