Plant Roots - Gregory, Peter J.

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Résumé :

An updated overview of plant root systems, covering their development, growth, interactions with soil, breeding and management

Plant Roots draws together information from plant and soil literature to illustrate how roots interact with soil, both to modify it and to obtain from it the resources required for the whole plant to grow. Emphasis is placed on whole plants and root systems, with appropriate references to the growing body of literature on plant molecular and cellular levels.

This newly revised and updated Second Edition maintains its balance between introducing the founding ideas and science underlying the topic while covering the most recent updates underpinned by new scientific methods and understanding. The author reviews recent advances in genomics, phenomics, other -omics technologies, computer modelling, and the study of 'model plants' such as Arabidopsis thaliana and rice which have led to major advances in understanding how roots grow and function. New crop varieties contributing to increased crop production, especially in nutrient poor and/or water-limited soils, are described together with new ways of managing root systems to improve crop performance and efficiency of resource use.

Sample topics discussed in Plant Roots include:

• The anatomy and growth of primary roots
• The development and properties of the rhizosphere
• Heterogeneity of structure, nutrient availability, and microbial communities experienced in field soils
• Differences in anatomy and morphology between different types (classes) of root and their consequences for activity as absorbers of water and nutrients
• How crops, forests, natural plant communities and the resources supporting them might be managed more effectively

Plant Roots is an essential source of reference aimed at students and professionals who already have some background knowledge of soils and plants and are seeking to understand cutting-edge updates in the field....

Biographie:

Peter J. Gregory Professor Emeritus, University of Reading, UK, is internationally known and respected for his work on roots and is the recipient of a Lifetime Achievement Award from the International Society of Root Research....

Sommaire:

Preface to Second Edition xiii

Preface to First Edition xv

1 Plants, Roots and the Soil 1

1.1 Evolution of Roots 2

1.2 Root and Shoot Coordination 6

1.2.1 Communication Between Roots and Shoots 6

1.2.2 Coordination of Growth 9

1.3 Roots and the Soil 11

1.3.1 Root-Soil Interface 12

1.3.2 Root-Induced Soil Processes 15

References 18

2 Roots and the Architecture of Root Systems 23

2.1 Nomenclature and Terminology 23

2.2 Root Anatomy 25

2.2.1 Primary Structure 26

2.2.2 Secondary Structure 32

2.3 Root Tip 36

2.3.1 Root Cap and Border Cells 36

2.3.2 Mucilage 39

2.4 Extension and Branching 42

2.4.1 Extension 42

2.4.2 Root Hairs 45

2.4.3 Branching 48

2.5 Adventitious and Specialised Roots 52

2.6 Architecture of Root Systems 57

References 62

3 Development and Growth of Root Systems 71

3.1 Measurement of Root Systems 71

3.1.1 Field Techniques 72

3.1.1.1 Extraction 72

3.1.1.2 Observation 74

3.1.1.3 Inference Techniques 78

3.1.2 Laboratory Techniques 78

3.1.3 Root Phenotyping 80

3.2 Root System Development and Phenology 82

3.3 Size and Distribution of Root Systems 84

3.3.1 Mass and Length 84

3.3.2 Depth of Rooting 91

3.3.3 Distribution of Roots 94

3.4 Root:Shoot Allocation of Dry Matter 96

3.5 Root Longevity and Turnover 97

3.6 Modelling of Root Systems 102

3.6.1 Depth and Distribution Models 102

3.6.2 Density-Based Diffusion Models 103

3.6.3 Root System Architectural Models 106

3.6.4 Crop Models 109

References 112

4 The Rhizosphere 123

4.1 Microbial Communities and Biochemical Changes 125

4.1.1 General Features 125

4.1.2 Nitrogen Availability 127

4.1.3 Phosphorus Availability 130

4.1.3.1 Root Hairs 131

4.1.3.2 Organic Anions 131

4.1.3.3 Enzymes 135

4.1.3.4 Arbuscular Mycorrhizal Fungi and the Hyphosphere 137

4.1.4 Availability of Other Nutrients 137

4.2 Rhizodeposition 139

4.2.1 Rhizodeposits - Quantities and Composition 139

4.2.2 Root Exudates 143

4.2.3 Carbon Sequestration by Soil 146

4.2.4 Root Exudates and Phytosiderophores 148

4.3 Rhizosphere Signalling 150

4.3.1 Microbiome-Root-Shoot Signalling 151

4.3.2 Cross-Kingdom Signalling 151

4.3.3 Gaseous Signals 153

4.4 Chemical and Physical Changes in the Rhizosphere 153

4.4.1 Chemical Changes 154

4.4.1.1 Changes in pH 154

4.4.1.2 Changes in Redox (Eh) Conditions 156

4.4.2 Soil Structure in the Rhizosphere 159

4.4.3 Soil Water 161

4.4.4 Engineering and Managing the Rhizosphere 163

References 164

5 Roots and the Biological Environment 177

5.1 Interactions of Roots with Soil Organisms 177

5.1.1 Root-Microbiome Signalling 177

5.1.2 Interactions with Bacteria 180

5.1.3 Interactions with Fungi 184

5.1.4 Interactions with Protozoa 185

5.1.5 Interactions with Meso-fauna 186

5.2 Endosymbiotic Associations 189

5.2.1 Mycorrhizas 190

5.2.2 Rhizobia and N Fixation 203

5.3 Root Pathogens and Parasitic Associations 209

5.3.1 Fungal Diseases 209

5.3.2 Nematodes 212

5.3.3 Parasitic Weeds 215

5.4 Root Herbivory by Insects 219

References 221

6 Roots and the Physico-Chemical Environment 233

6.1 Temperature 233

6.1.1 Root Development and Growth 235

6.1.2 Root Orientation and Root System Architecture 238

6.1.3 Extremes of C...