Science and the Garden: The Scientific Basis of Horticultural Practice

395 Pages·2016·21.13 MB·English

by  David S. Ingram

Science
a n dG arden
the
The ScienTific BaSiS
of horTiculTural PracTice
third edition
edited by david S. ingram, daphne Vince-Prue
and Peter J. Gregory

Science and the Garden
About The Royal Horticultural Society
The Royal Horticultural Society is the UK’s leading gardening charity dedicated to advancing horticulture and pro-
moting good gardening. Its charitable work includes providing expert advice and information, training the next
generation of gardeners, creating hands-on opportunities for children to grow plants and conducting research into
plants, pests and environmental issues affecting gardeners.
Science and
the Garden
The scientific basis of
horticultural practice
EDITED BY
David S. Ingram
Daphne Vince-Prue
Peter J. Gregory
THIRD EDITION
This edition first published 2016 © 2016 by John Wiley & Sons, Ltd.
Published in association with the Royal Horticultural Society.
First published 2002 by Blackwell Science Ltd; Second Edition 2008 by Blackwell Publishing Ltd.
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Library of Congress Cataloging-in-Publication Data
Science and the garden : the scientific basis of horticultural practice / edited by David S. Ingram, Daphne
Vince-Prue, Peter J. Gregory. – Third edition.
pages cm
Includes bibliographical references and index.
ISBN 978-1-118-77843-2 (pbk.)
1. Horticulture. 2. Gardening. I. Ingram, David S. II. Vince-Prue, Daphne. III. Gregory, P. J.
SB318.S29 2016
635—dc23
2015024749
A catalogue record for this book is available from the British Library.
Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may
not be available in electronic books.
Cover images: Large image [of garden steps and gate; Fig. 1.1 in 3rd edition] - Photograph © David S.
Ingram. Top small image [flower with hoverflies; Fig. 18.3c in 3rd edition] - Photograph © and reproduced
courtesy of the University of Warwick.
Centre small image [rooted cutting; Fig. 11.5c in 3rd edition] - Photograph © and courtesy of the Royal
Horticultural Society. Bottom small image [half flower of Antirrhinum; Fig. 3.5 in 3rd edition] - Scan and
© John Bebbington, FRPS.
Set in 8.5/12pt Meridien by Aptara Inc., New Delhi, India
1 2016
Contents
Preface to third edition, xiii Connecting with the stem, 25
Preface to second edition, xiv Leaf fall, 25
Leaf patterns: phyllotaxy, 26
Preface to first edition, xv
Variations on a theme, 26
1 Diversity in the plant world, 1 The stem: reach for the sky, 27
Summary, 1 The growing point, 27
Introduction, 1 Forming new leaves, 28
Creating order out of disorder, 1 A tower of strength, 28
Colonisation of the land, 4 Secondary thickening: the formation of wood and
Communities and the diversity of life forms, 6 bark, 29
Conclusion, 12 Bark, 30
Further reading, 13 Stem modifications, 31
Authors and affiliations, 13 The root: mining for minerals and water, 32
The structure and growth of the root, 32
2 The plant body: structure and function, 14 Storage roots and other modifications, 33
Summary 14 Nitrogen fixation, 34
Introduction, 14 Mycorrhizas, 34
Energy flow in the biosphere: photosynthesis and Conclusion, 35
respiration, 14 Further reading, 36
The light reaction of photosynthesis, 14 Authors and affiliations, 36
The dark reaction of photosynthesis, 14
C-3, C-4 and CAM plants, 14 3 Reproduction: Securing the future, 37
Respiration, 16 Summary, 37
Photorespiration, 16 Introduction, 37
Global significance of photosynthesis, 16 Vegetative reproduction, 37
The leaf: into the labyrinth, 17 Sexual reproduction, 38
The manufacturing centre, 17 Cones and flowers, 38
Cells, 17 Alternation of generations, 41
Water relations of cells, 17 Floral diagrams and formulae, 41
Layout of the leaf, 17 Seeds and fruits, 42
Controlling gas and water exchange, 17 Other fruits, 42
Protection against harmful radiation, 19 Conclusion, 44
Palisade tissues: the sites of photosynthesis, 21 Further reading, 44
The transport system, 21 Authors and affiliations, 44
Movement of water, minerals and hormones in the
4 Naming plants, 45
xylem, 21
Summary, 45
Transport of carbohydrates and hormones in the
Introduction, 45
phloem, 22
Latin botanical names, 45
Producing new xylem and phloem: the cambium, 24
The bundle sheath, 24
vv
vi Contents
Taxonomy: order in diversity, 47 Conclusion, 74
New developments, 47 Further reading, 74
Cultivated plant taxonomy, 48 Authors and affiliations, 74
Distinctiveness, 49
Uniformity, 49 6 Summary, 75
Introduction, 75
Stability, 49
Why plants change their names, 49 Why do plants need soil?, 75
What do plants want from the soil?, 75
Taxonomic changes, 49
How soils are formed, 75
Nomenclatural changes, 50
Physical properties of soils, 76
Misidentification, 50
Chemical properties of soils, 79
The quest for stability and linking information
Biological properties of soils, 80
systems, 50
Roots and soils, 82
Botanical plant name stability, 51
Conclusion, 85
Cultivated plant name stability, 51
Further reading, 85
How to identify a plant, 52
Authors and affiliations, 85
Conclusion, 53
Further reading, 53
7 Soil cultivation and fertility, 86
Authors and affiliations, 54
Summary, 86
5 Selecting and breeding plants, 55 Cultivating the soil, 86
Summary, 55 Managing soil nutrients, 88
Introduction: adaptation and design, 55 Sources of the major plant nutrients, 89
Genes, 56 Fertilisers, 91
Manures, 93
Gene regulation, 58
Composts, 93
Chromosomes, 59
Managing soil pH, 94
DNA replication, 60
Genomes, 61 Managing water, 96
Gamete formation, 61 Soil-less growing media, 98
Conclusion, 101
Recombination, 62
Further reading, 101
Allelic variation, 62
Mutation, 62 Authors and affiliations, 101
Transposons, 62
8 The plant environment: Light and water, 102
Somatic and germ line mutations, 64
Summary, 102
Chimeras, 64
Introduction, 102
Heterozygosity and homozygosity, 67
Light and photosynthesis, 102
Dominant and recessive alleles, 67
The measurement of light, 103
Breeding systems, 68
Controlling gas exchange, 104
Breeding inbred lines, 69
Effect of the environment on photosynthesis, 105
Breeding open-pollinated populations, 69
The effects of shade, 105
Clonal propagation, 70
Water, 108
F1 hybrid breeding, 70
How water loss from the leaf is controlled, 109
Wide hybridisation, 71
The mechanisms of stomatal opening and closure, 109
Somatic variation, 71
Water stress, 109
Somatic hybridisation, 71
The problem of drought, 110
Recombinant DNA technology, 72
Physical structures that help to conserve water, 111
Marker-assisted breeding, 72
Biochemical pathways that help conserve
Genome sequencing, 72
water, 113
Genetic modification, 73
Contents vii
C-4 plants, 113 Germination, 144
Crassulacean acid metabolism, 114 Alternating temperatures and light, 144
Salinity, 115 Phytochrome, 145
Too much water, 115 Nitrate and smoke, 145
Aquatic plants, 117 Some practical considerations, 146
Watering in the garden, 117 Collecting seeds, and F1 hybrids, 147
Choosing plants for particular conditions, 117 Further reading, 148
Conclusion, 117 Authors and affiliations, 148
Further reading, 118
Authors and affiliations, 119 11 Vegetative propagation, 149
Summary, 149
9 Plants and seasons, 120
Introduction, 149
Summary, 120
Characteristics of vegetative propagation
Introduction, 120
and its value to gardeners, 149
Day-length, 120
How plants regenerate, 150
Mechanisms for the control of flowering by day-length,
Practical propagation, 154
124
Softwood cuttings, 154
Detection of day-length by the leaf, 127
Hardwood cuttings, 156
Chemical nature of the flowering signal, 128
Evergreen cuttings, 157
Plant hormones and flowering, 129
Leaf cuttings, 157
Formation of storage organs in response to day-length,
131 Root cuttings, 158
Day-length and the control of leaf-fall Layering, 159
and dormancy, 133 Division, 160
Temperature, 134 Other organs, 161
Vernalisation, 135 Grafting and budding, 161
The advantages of vernalisation Micropropagation, 163
for a plant, 136 Conclusion, 164
Effective temperatures for vernalisation, 136 Further reading, 165
Devernalisation, 136 Authors and affiliations, 165
Direct effects of temperature on flowering, 136
Damage caused by sub-zero temperatures, 136 12 Size and form, 166
Breaking winter dormancy, 137 Summary, 166
Increasing temperatures, 138 Introduction, 166
Conclusion, 138
How size is controlled, 166
Further reading, 138
Endogenous factors, 166
Authors and affiliations, 138
External factors controlling size, 167
How form is controlled, 168
10 Growing plants from seed, 139
External factors, 168
Summary, 139
Introduction, 139 Form and size can be manipulated by
Seed production and germination, 139 the gardener, 169
Recalcitrant seeds, 140 Pruning, 169
Seed storage, 141 Special training methods, 170
Dormancy, 142 Special forms, 171
Physiological dormancy, 142 Conclusions, 173
Morphological dormancy, 142 Further reading, 173
Physical dormancy, 143 Authors and affiliations, 174
viii Contents
13 Colour, scent and sound in the garden, 175 Seasonality, 202
Summary, 175 Climate, 203
Introduction, 175 Difference between climate and weather, 203
Colour in plants, 175 Global climatic zones, 204
The perception of colour, 175 UK climate influences, 204
Plant pigments, 176 Conclusion, 205
Pigments as attractants, 177 Further reading, 205
Variegation, 178 Authors and affiliations, 205
Chimeras, 178
Transposons, 178 15 Climate and other environmental changes, 206
Summary, 206
Pattern genes, 178
Global environmental change, 206
Viruses, 178
Changes in atmospheric composition, 206
Tulipomania, 179
Climate change and climate variation, 208
Environmental factors influencing colour, 179
Changes in nutrient cycles, 211
Seasonal changes, 180
Other environmental changes, 212
The use of colour in the garden, 180
Conclusions, 213
Scent and flavour, 181
Further reading, 213
Scent wheels, 184
Authors and affiliations, 213
Sound, 185
The nature, perception and appreciation of sound, 185
16 Protected cultivation, 214
Sounds for pleasure, 186
Summary, 214
Conclusion, 190
Why protect plants?, 214
Further reading, 190
What are the benefits?, 214
Authors and affiliations, 190
Temperature, 215
14 Climate and weather, 191 Development, 215
Summary, 191 Stem growth, 216
Introduction, 191 Cold tolerance, 217
Temperature, 192 Principles of protection, 217
Heat, 192 Energy transfer, 217
Cold, 193 The importance of light, 217
Cladding materials, 218
Hardiness, 194
Growing season, 194 Glass, 218
Soil temperature, 196 Film plastics, 218
Precipitation, 197 Bubble plastic sheets, 219
Impacts of rainfall, snow and hail, 197 Polycarbonate sheets, 219
Types of protection, 219
Seasonality of precipitation, 197
Extremes of rainfall, 197 Mulches, 219
Humidity, 198 Horticultural fleeces and meshes, 219
Wind, 198 Cloches and cold frames, 219
Nature and causes, 199 Tunnels, 220
Effects of wind, 199 Greenhouses, 220
Pressure, 199 Systems to be added, 222
Light, 200 Heating systems, 222
Day-length, 200 Ventilation, 222
Angle of the sun, 200 Energy saving, 222
Light intensity, 201 Carbon dioxide (CO2), 223
Lighting, 224
Sunshine hours, 202