Science and the Garden, 3d Edition

Science and the Garden, 3d Edition

Most conventional gardening books concentrate on how and when to carry out horticultural tasks such as pruning, seed sowing and taking cuttings. Science and the Garden, Third Edition is unique in explaining in straightforward terms some of the science that underlies these practices. It is principally a book of 'Why' – Why are plants green? Why do some plants only flower in the autumn? Why do lateral buds begin to grow when the terminal bud is removed by pruning? Why are some plants successful as weeds? Why does climate variability and change mean change for gardeners? But it also goes on to deal with the 'How', providing rationale behind the practical advice.
The coverage is wide-ranging and comprehensive and includes: the diversity, structure, functioning and reproduction of garden plants; nomenclature and classification; genetics and plant breeding; soil properties and soil management; environmental factors affecting growth and development; methods of propagation; size and form; colour, scent and sound; climate; environmental change; protected cultivation; pest, disease and weed diversity and control; post-harvest management and storage; garden ecology and conservation; sustainable horticulture; gardens and human health and wellbeing; and gardens for science.
This expanded and fully updated Third Edition of Science and the Garden includes two completely new chapters on important topics:
•    Climate and Other Environmental Changes
•    Health, Wellbeing and Socio-cultural Benefits
Many of the other chapters have been completely re-written or extensively revised and expanded, often with new authors and/or illustrators, and the remainder have all been carefully updated and re-edited. Published in collaboration with the Royal Horticultural Society, reproduced in full colour throughout, carefully edited and beautifully produced, this new edition remains a key text for students of horticulture and will also appeal to amateur and professional gardeners wishing to know more about the fascinating science behind the plants and practices that are the everyday currency of gardening.

Τable of Contents

Preface to third edition, xiii
Preface to second edition, xiv
Preface to first edition, xv
1 Diversity in the plant world, 1
Summary, 1
Introduction, 1
Creating order out of disorder, 1
Colonisation of the land, 4
Communities and the diversity of life forms, 6
Conclusion, 12
Further reading, 13
Authors and affiliations, 13
2 The plant body: structure and function, 14
Summary 14
Introduction, 14
Energy flow in the biosphere: photosynthesis and respiration, 14
The light reaction of photosynthesis, 14
The dark reaction of photosynthesis, 14
C-3, C-4 and CAM plants, 14
Respiration, 16
Photorespiration, 16
Global significance of photosynthesis, 16
The leaf: into the labyrinth, 17
The manufacturing centre, 17
Cells, 17
Water relations of cells, 17
Layout of the leaf, 17
Controlling gas and water exchange, 17
Protection against harmful radiation, 19
Palisade tissues: the sites of photosynthesis, 21
The transport system, 21
Movement of water, minerals and hormones in the xylem, 21
Transport of carbohydrates and hormones in the phloem, 22
Producing new xylem and phloem: the cambium, 24
The bundle sheath, 24
Connecting with the stem, 25
Leaf fall, 25
Leaf patterns: phyllotaxy, 26
Variations on a theme, 26
The stem: reach for the sky, 27
The growing point, 27
Forming new leaves, 28
A tower of strength, 28
Secondary thickening: the formation of wood and bark, 29
Bark, 30
Stem modifications, 31
The root: mining for minerals and water, 32
The structure and growth of the root, 32
Storage roots and other modifications, 33
Nitrogen fixation, 34
Mycorrhizas, 34
Conclusion, 35
Further reading, 36
Authors and affiliations, 36
3 Reproduction: Securing the future, 37
Summary, 37
Introduction, 37
Vegetative reproduction, 37
Sexual reproduction, 38
Cones and flowers, 38
Alternation of generations, 41
Floral diagrams and formulae, 41
Seeds and fruits, 42
Other fruits, 42
Conclusion, 44
Further reading, 44
Authors and affiliations, 44
4 Naming plants, 45
Summary, 45
Introduction, 45
Latin botanical names, 45
Taxonomy: order in diversity, 47
New developments, 47
Cultivated plant taxonomy, 48
Distinctiveness, 49
Uniformity, 49
Stability, 49
Why plants change their names, 49
Taxonomic changes, 49
Nomenclatural changes, 50
Misidentification, 50
The quest for stability and linking information systems, 50
Botanical plant name stability, 51
Cultivated plant name stability, 51
How to identify a plant, 52
Conclusion, 53
Further reading, 53
Authors and affiliations, 54
5 Selecting and breeding plants, 55
Summary, 55
Introduction: adaptation and design, 55
Genes, 56
Gene regulation, 58
Chromosomes, 59
DNA replication, 60
Genomes, 61
Gamete formation, 61
Recombination, 62
Allelic variation, 62
Mutation, 62
Transposons, 62
Somatic and germ line mutations, 64
Chimeras, 64
Heterozygosity and homozygosity, 67
Dominant and recessive alleles, 67
Breeding systems, 68
Breeding inbred lines, 69
Breeding open-pollinated populations, 69
Clonal propagation, 70
F1 hybrid breeding, 70
Wide hybridisation, 71
Somatic variation, 71
Somatic hybridisation, 71
Recombinant DNA technology, 72
Marker-assisted breeding, 72
Genome sequencing, 72
Genetic modification, 73
Conclusion, 74
Further reading, 74
Authors and affiliations, 74
6 Summary, 75
Introduction, 75
Why do plants need soil?, 75
What do plants want from the soil?, 75
How soils are formed, 75
Physical properties of soils, 76
Chemical properties of soils, 79
Biological properties of soils, 80
Roots and soils, 82
Conclusion, 85
Further reading, 85
Authors and affiliations, 85
7 Soil cultivation and fertility, 86
Summary, 86
Cultivating the soil, 86
Managing soil nutrients, 88
Sources of the major plant nutrients, 89
Fertilisers, 91
Manures, 93
Composts, 93
Managing soil pH, 94
Managing water, 96
Soil-less growing media, 98
Conclusion, 101
Further reading, 101
Authors and affiliations, 101
8 The plant environment: Light and water, 102
Summary, 102
Introduction, 102
Light and photosynthesis, 102
The measurement of light, 103
Controlling gas exchange, 104
Effect of the environment on photosynthesis, 105
The effects of shade, 105
Water, 108
How water loss from the leaf is controlled, 109
The mechanisms of stomatal opening and closure, 109
Water stress, 109
The problem of drought, 110
Physical structures that help to conserve water, 111
Biochemical pathways that help conserve water, 113
C-4 plants, 113
Crassulacean acid metabolism, 114
Salinity, 115
Too much water, 115
Aquatic plants, 117
Watering in the garden, 117
Choosing plants for particular conditions, 117
Conclusion, 117
Further reading, 118
Authors and affiliations, 119
9 Plants and seasons, 120
Summary, 120
Introduction, 120
Day-length, 120
Mechanisms for the control of flowering by day-length, 124
Detection of day-length by the leaf, 127
Chemical nature of the flowering signal, 128
Plant hormones and flowering, 129
Formation of storage organs in response to day-length, 131
Day-length and the control of leaf-fall and dormancy, 133
Temperature, 134
Vernalisation, 135
The advantages of vernalisation for a plant, 136
Effective temperatures for vernalisation, 136
Devernalisation, 136
Direct effects of temperature on flowering, 136
Damage caused by sub-zero temperatures, 136
Breaking winter dormancy, 137
Increasing temperatures, 138
Conclusion, 138
Further reading, 138
Authors and affiliations, 138
10 Growing plants from seed, 139
Summary, 139
Introduction, 139
Seed production and germination, 139
Recalcitrant seeds, 140
Seed storage, 141
Dormancy, 142
Physiological dormancy, 142
Morphological dormancy, 142
Physical dormancy, 143
Germination, 144
Alternating temperatures and light, 144
Phytochrome, 145
Nitrate and smoke, 145
Some practical considerations, 146
Collecting seeds, and F1 hybrids, 147
Further reading, 148
Authors and affiliations, 148
11 Vegetative propagation, 149
Summary, 149
Introduction, 149
Characteristics of vegetative propagation and its value to gardeners, 149
How plants regenerate, 150
Practical propagation, 154
Softwood cuttings, 154
Hardwood cuttings, 156
Evergreen cuttings, 157
Leaf cuttings, 157
Root cuttings, 158
Layering, 159
Division, 160
Other organs, 161
Grafting and budding, 161
Micropropagation, 163
Conclusion, 164
Further reading, 165
Authors and affiliations, 165
12 Size and form, 166
Summary, 166
Introduction, 166
How size is controlled, 166
Endogenous factors, 166
External factors controlling size, 167
How form is controlled, 168
External factors, 168
Form and size can be manipulated by the gardener, 169
Pruning, 169
Special training methods, 170
Special forms, 171
Conclusions, 173
Further reading, 173
Authors and affiliations, 174
13 Colour, scent and sound in the garden, 175
Summary, 175
Introduction, 175
Colour in plants, 175
The perception of colour, 175
Plant pigments, 176
Pigments as attractants, 177
Variegation, 178
Chimeras, 178
Transposons, 178
Pattern genes, 178
Viruses, 178
Tulipomania, 179
Environmental factors influencing colour, 179
Seasonal changes, 180
The use of colour in the garden, 180
Scent and flavour, 181
Scent wheels, 184
Sound, 185
The nature, perception and appreciation of sound, 185
Sounds for pleasure, 186
Conclusion, 190
Further reading, 190
Authors and affiliations, 190
14 Climate and weather, 191
Summary, 191
Introduction, 191
Temperature, 192
Heat, 192
Cold, 193
Hardiness, 194
Growing season, 194
Soil temperature, 196
Precipitation, 197
Impacts of rainfall, snow and hail, 197
Seasonality of precipitation, 197
Extremes of rainfall, 197
Humidity, 198
Wind, 198
Nature and causes, 199
Effects of wind, 199
Pressure, 199
Light, 200
Day-length, 200
Angle of the sun, 200
Light intensity, 201
Sunshine hours, 202
Seasonality, 202
Climate, 203
Difference between climate and weather, 203
Global climatic zones, 204
UK climate influences, 204
Conclusion, 205
Further reading, 205
Authors and affiliations, 205
15 Climate and other environmental changes, 206
Summary, 206
Global environmental change, 206
Changes in atmospheric composition, 206
Climate change and climate variation, 208
Changes in nutrient cycles, 211
Other environmental changes, 212
Conclusions, 213
Further reading, 213
Authors and affiliations, 213
16 Protected cultivation, 214
Summary, 214
Why protect plants?, 214
What are the benefits?, 214
Temperature, 215
Development, 215
Stem growth, 216
Cold tolerance, 217
Principles of protection, 217
Energy transfer, 217
The importance of light, 217
Cladding materials, 218
Glass, 218
Film plastics, 218
Bubble plastic sheets, 219
Polycarbonate sheets, 219
Types of protection, 219
Mulches, 219
Horticultural fleeces and meshes, 219
Cloches and cold frames, 219
Tunnels, 220
Greenhouses, 220
Systems to be added, 222
Heating systems, 222
Ventilation, 222
Energy saving, 222
Carbon dioxide (CO2), 223
Lighting, 224
Irrigation, 224
Control systems, 225
Biological control, 225
Mechanisation, 225
Special cases, 225
Plant growth regulators, 226
Does protection have disadvantages?, 226
Crops grown under protection, 227
Chrysanthemum, 227
Cucumber, 228
Lettuce, leafy salads and other salad vegetables, 229
Poinsettia, 229
Strawberry, 230
Tomato, 231
Pot plants, 233
Conclusions, 233
Further reading, 233
Authors and affiliations, 233
17 The diversity of the undesirables, 234
Summary, 234
Introduction, 234
Pests, 234
Nematodes (eelworms), 234
Molluscs: slugs and snails, 234
Mites, 234
Insects, 234
Birds and mammals, 235
Diseases, 235
Opportunists, 237
Necrotrophs: destructive parasites, 237
Biotrophs: non-destructive parasites, 237
Hemibiotrophs, 237
Symptoms caused by the different types of pathogenic microorganisms, 237
Weeds, 239
Annual weeds, 239
Perennial weeds, 239
Weed origins, 239
Useful weeds, 240
Intraspecific diversity, 241
New pests and diseases, 242
Deciding whether an organism is a problem, 243
When is a pest a pest?, 243
The importance of weather, 244
When to control pests, 244
When is a disease a problem?, 244
Weed problems, 245
Poisonous and irritant plants, 246
Conclusion, 247
Further reading, 247
Authors and affiliations, 247
18 Controlling the undesirables, 248
Summary, 248
Introduction, 248
Keeping out the undesirables, 248
The role of the UK government, 248
The role of the horticultural industry, 249
The role of gardeners, 250
Know your enemy, 252
Control, 253
Cultural practices (‘good gardening’), 253
Physical methods, 255
Host resistance or tolerance, 256
Biological control, 257
Chemical control, 259
Conclusions, 261
Further reading and sources of information, 261
Books, 261
Websites, 261
Authors and affiliations, 261
19 Maturation, ripening and storage, 262
Summary, 262
Introduction, 262
Changes in metabolism and ethylene synthesis, 262
Respiration and water loss, 262
Ethylene, 263
Maturation and ripening, 264
Seeds, 264
Fruits, 265
Vegetables, 265
Cut flowers, 266
Pre-harvest influences on storage quality, 266
Diseases and disorders, 266
Climatic factors, 267
Field factors, 268
Varietal factors, 268
Harvesting, handling and preparation for storage, 269
Time of harvest, 269
Handling, 269
Post-harvest treatments, 270
The storage environment, 271
Fresh produce, 271
Low-temperature storage methods, 271
Controlled atmosphere (CA) storage, 272
Seeds, 273
Trends in commercial storage, 274
Non-commercial storage, 275
Seeds, 275
Soft fruits, 275
Stone fruits, 275
Pome fruits, 275
Vegetables, 276
Cut flowers, 276
Conclusion, 276
Further reading, 276
Authors and affiliations, 277
20 Garden ecology, 278
Summary, 278
Ecology and ecosystems, 278
Ecology: open and closed systems, 278
Food webs, 278
Nutrient and carbon cycling, 279
Cycling at the global scale, 280
Habitats, 282
Climate and soil tolerance, 282
Natural processes and human land management, 283
Slow-growing and fast-growing plants, 284
Competition and herbivory, 286
Habitat creation, 286
Biodiversity, 288
Why are there so many plants?, 288
Diversity and stability, 289
Ecological succession and the balance of nature, 289
Unstable dynamics, 290
Conclusions, 290
Further reading, 291
Authors and affiliations, 291
21 Garden wildlife and conservation, 292
Summary, 292
Natives and aliens, 292
Gardens and native flora, 292
Native species and the Southwood hypothesis, 293
Invasive plants and animals, 294
Gardens and the wider environment, 295
Wildlife in gardens, 295
Ecosystem services, 296
Conservation in gardens, 296
Conservation of wild plants, 296
Conservation of cultivars, 297
Conclusions, 298
Websites and further reading, 298
Websites, 298
Books, 298
Authors and affiliations, 298
22 Low-input and low-impact gardening, 299
Summary, 299
Introduction, 299
Conservation of resources in the garden, 299
Soil nutrients and organic matter, 299
Water management, 300
Recycling other materials, 302
Wildlife, 302
Carbon and greenhouse gas emissions, 304
The problem of peat, 305
Environmental footprint of lawns, 305
Cash benefit of low-intensity garden management, 306
Conclusions, 306
Further reading, 306
Websites, 306
Books, 306
Authors and affiliations, 306
23 Health, well-being and socio-cultural benefits, 307
Summary, 307
Gardens and ecosystem service provision, 307
Why garden?, 307
Gardens and green therapy, 309
Restorative landscapes, 313
Horticultural therapy, 314
Health risks, 315
Crime and antisocial behaviour, 316
Social and educational opportunities, 316
Children and green space, 317
Encouraging a balanced diet, 317
Gardening and attitudes to the wider environment, 318
Conclusions, 319
Further reading, 319
Author and affiliations, 319
24 Gardens for science, 320
Summary, 320
Introduction, 320
Botanic gardens, 320
European origins and development in the United Kingdom, 320
Collections, 322
Research, 324
Conservation, education and training, 325
The gardens of horticultural societies, 325
Private and small commercial gardens, 325
Universities and independent research institutes, 326
Conclusion, 328
Further reading, 328
Authors and affiliations, 328
Glossary, 329
Index, 355