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 BenefitsMany 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.

Preface to third edition, xiiiPreface to second edition, xivPreface to first edition, xv1 Diversity in the plant world, 1Summary, 1Introduction, 1Creating order out of disorder, 1Colonisation of the land, 4Communities and the diversity of life forms, 6Conclusion, 12Further reading, 13Authors and affiliations, 132 The plant body: structure and function, 14Summary 14Introduction, 14Energy flow in the biosphere: photosynthesis and respiration, 14The light reaction of photosynthesis, 14The dark reaction of photosynthesis, 14C-3, C-4 and CAM plants, 14Respiration, 16Photorespiration, 16Global significance of photosynthesis, 16The leaf: into the labyrinth, 17The manufacturing centre, 17Cells, 17Water relations of cells, 17Layout of the leaf, 17Controlling gas and water exchange, 17Protection against harmful radiation, 19Palisade tissues: the sites of photosynthesis, 21The transport system, 21Movement of water, minerals and hormones in the xylem, 21Transport of carbohydrates and hormones in the phloem, 22Producing new xylem and phloem: the cambium, 24The bundle sheath, 24Connecting with the stem, 25Leaf fall, 25Leaf patterns: phyllotaxy, 26Variations on a theme, 26The stem: reach for the sky, 27The growing point, 27Forming new leaves, 28A tower of strength, 28Secondary thickening: the formation of wood and bark, 29Bark, 30Stem modifications, 31The root: mining for minerals and water, 32The structure and growth of the root, 32Storage roots and other modifications, 33Nitrogen fixation, 34Mycorrhizas, 34Conclusion, 35Further reading, 36Authors and affiliations, 363 Reproduction: Securing the future, 37Summary, 37Introduction, 37Vegetative reproduction, 37Sexual reproduction, 38Cones and flowers, 38Alternation of generations, 41Floral diagrams and formulae, 41Seeds and fruits, 42Other fruits, 42Conclusion, 44Further reading, 44Authors and affiliations, 444 Naming plants, 45Summary, 45Introduction, 45Latin botanical names, 45Taxonomy: order in diversity, 47New developments, 47Cultivated plant taxonomy, 48Distinctiveness, 49Uniformity, 49Stability, 49Why plants change their names, 49Taxonomic changes, 49Nomenclatural changes, 50Misidentification, 50The quest for stability and linking information systems, 50Botanical plant name stability, 51Cultivated plant name stability, 51How to identify a plant, 52Conclusion, 53Further reading, 53Authors and affiliations, 545 Selecting and breeding plants, 55Summary, 55Introduction: adaptation and design, 55Genes, 56Gene regulation, 58Chromosomes, 59DNA replication, 60Genomes, 61Gamete formation, 61Recombination, 62Allelic variation, 62Mutation, 62Transposons, 62Somatic and germ line mutations, 64Chimeras, 64Heterozygosity and homozygosity, 67Dominant and recessive alleles, 67Breeding systems, 68Breeding inbred lines, 69Breeding open-pollinated populations, 69Clonal propagation, 70F1 hybrid breeding, 70Wide hybridisation, 71Somatic variation, 71Somatic hybridisation, 71Recombinant DNA technology, 72Marker-assisted breeding, 72Genome sequencing, 72Genetic modification, 73Conclusion, 74Further reading, 74Authors and affiliations, 746 Summary, 75Introduction, 75Why do plants need soil?, 75What do plants want from the soil?, 75How soils are formed, 75Physical properties of soils, 76Chemical properties of soils, 79Biological properties of soils, 80Roots and soils, 82Conclusion, 85Further reading, 85Authors and affiliations, 857 Soil cultivation and fertility, 86Summary, 86Cultivating the soil, 86Managing soil nutrients, 88Sources of the major plant nutrients, 89Fertilisers, 91Manures, 93Composts, 93Managing soil pH, 94Managing water, 96Soil-less growing media, 98Conclusion, 101Further reading, 101Authors and affiliations, 1018 The plant environment: Light and water, 102Summary, 102Introduction, 102Light and photosynthesis, 102The measurement of light, 103Controlling gas exchange, 104Effect of the environment on photosynthesis, 105The effects of shade, 105Water, 108How water loss from the leaf is controlled, 109The mechanisms of stomatal opening and closure, 109Water stress, 109The problem of drought, 110Physical structures that help to conserve water, 111Biochemical pathways that help conserve water, 113C-4 plants, 113Crassulacean acid metabolism, 114Salinity, 115Too much water, 115Aquatic plants, 117Watering in the garden, 117Choosing plants for particular conditions, 117Conclusion, 117Further reading, 118Authors and affiliations, 1199 Plants and seasons, 120Summary, 120Introduction, 120Day-length, 120Mechanisms for the control of flowering by day-length, 124Detection of day-length by the leaf, 127Chemical nature of the flowering signal, 128Plant hormones and flowering, 129Formation of storage organs in response to day-length, 131Day-length and the control of leaf-fall and dormancy, 133Temperature, 134Vernalisation, 135The advantages of vernalisation for a plant, 136Effective temperatures for vernalisation, 136Devernalisation, 136Direct effects of temperature on flowering, 136Damage caused by sub-zero temperatures, 136Breaking winter dormancy, 137Increasing temperatures, 138Conclusion, 138Further reading, 138Authors and affiliations, 13810 Growing plants from seed, 139Summary, 139Introduction, 139Seed production and germination, 139Recalcitrant seeds, 140Seed storage, 141Dormancy, 142Physiological dormancy, 142Morphological dormancy, 142Physical dormancy, 143Germination, 144Alternating temperatures and light, 144Phytochrome, 145Nitrate and smoke, 145Some practical considerations, 146Collecting seeds, and F1 hybrids, 147Further reading, 148Authors and affiliations, 14811 Vegetative propagation, 149Summary, 149Introduction, 149Characteristics of vegetative propagation and its value to gardeners, 149How plants regenerate, 150Practical propagation, 154Softwood cuttings, 154Hardwood cuttings, 156Evergreen cuttings, 157Leaf cuttings, 157Root cuttings, 158Layering, 159Division, 160Other organs, 161Grafting and budding, 161Micropropagation, 163Conclusion, 164Further reading, 165Authors and affiliations, 16512 Size and form, 166Summary, 166Introduction, 166How size is controlled, 166Endogenous factors, 166External factors controlling size, 167How form is controlled, 168External factors, 168Form and size can be manipulated by the gardener, 169Pruning, 169Special training methods, 170Special forms, 171Conclusions, 173Further reading, 173Authors and affiliations, 17413 Colour, scent and sound in the garden, 175Summary, 175Introduction, 175Colour in plants, 175The perception of colour, 175Plant pigments, 176Pigments as attractants, 177Variegation, 178Chimeras, 178Transposons, 178Pattern genes, 178Viruses, 178Tulipomania, 179Environmental factors influencing colour, 179Seasonal changes, 180The use of colour in the garden, 180Scent and flavour, 181Scent wheels, 184Sound, 185The nature, perception and appreciation of sound, 185Sounds for pleasure, 186Conclusion, 190Further reading, 190Authors and affiliations, 19014 Climate and weather, 191Summary, 191Introduction, 191Temperature, 192Heat, 192Cold, 193Hardiness, 194Growing season, 194Soil temperature, 196Precipitation, 197Impacts of rainfall, snow and hail, 197Seasonality of precipitation, 197Extremes of rainfall, 197Humidity, 198Wind, 198Nature and causes, 199Effects of wind, 199Pressure, 199Light, 200Day-length, 200Angle of the sun, 200Light intensity, 201Sunshine hours, 202Seasonality, 202Climate, 203Difference between climate and weather, 203Global climatic zones, 204UK climate influences, 204Conclusion, 205Further reading, 205Authors and affiliations, 20515 Climate and other environmental changes, 206Summary, 206Global environmental change, 206Changes in atmospheric composition, 206Climate change and climate variation, 208Changes in nutrient cycles, 211Other environmental changes, 212Conclusions, 213Further reading, 213Authors and affiliations, 21316 Protected cultivation, 214Summary, 214Why protect plants?, 214What are the benefits?, 214Temperature, 215Development, 215Stem growth, 216Cold tolerance, 217Principles of protection, 217Energy transfer, 217The importance of light, 217Cladding materials, 218Glass, 218Film plastics, 218Bubble plastic sheets, 219Polycarbonate sheets, 219Types of protection, 219Mulches, 219Horticultural fleeces and meshes, 219Cloches and cold frames, 219Tunnels, 220Greenhouses, 220Systems to be added, 222Heating systems, 222Ventilation, 222Energy saving, 222Carbon dioxide (CO2), 223Lighting, 224Irrigation, 224Control systems, 225Biological control, 225Mechanisation, 225Special cases, 225Plant growth regulators, 226Does protection have disadvantages?, 226Crops grown under protection, 227Chrysanthemum, 227Cucumber, 228Lettuce, leafy salads and other salad vegetables, 229Poinsettia, 229Strawberry, 230Tomato, 231Pot plants, 233Conclusions, 233Further reading, 233Authors and affiliations, 23317 The diversity of the undesirables, 234Summary, 234Introduction, 234Pests, 234Nematodes (eelworms), 234Molluscs: slugs and snails, 234Mites, 234Insects, 234Birds and mammals, 235Diseases, 235Opportunists, 237Necrotrophs: destructive parasites, 237Biotrophs: non-destructive parasites, 237Hemibiotrophs, 237Symptoms caused by the different types of pathogenic microorganisms, 237Weeds, 239Annual weeds, 239Perennial weeds, 239Weed origins, 239Useful weeds, 240Intraspecific diversity, 241New pests and diseases, 242Deciding whether an organism is a problem, 243When is a pest a pest?, 243The importance of weather, 244When to control pests, 244When is a disease a problem?, 244Weed problems, 245Poisonous and irritant plants, 246Conclusion, 247Further reading, 247Authors and affiliations, 24718 Controlling the undesirables, 248Summary, 248Introduction, 248Keeping out the undesirables, 248The role of the UK government, 248The role of the horticultural industry, 249The role of gardeners, 250Know your enemy, 252Control, 253Cultural practices ('good gardening'), 253Physical methods, 255Host resistance or tolerance, 256Biological control, 257Chemical control, 259Conclusions, 261Further reading and sources of information, 261Books, 261Websites, 261Authors and affiliations, 26119 Maturation, ripening and storage, 262Summary, 262Introduction, 262Changes in metabolism and ethylene synthesis, 262Respiration and water loss, 262Ethylene, 263Maturation and ripening, 264Seeds, 264Fruits, 265Vegetables, 265Cut flowers, 266Pre-harvest influences on storage quality, 266Diseases and disorders, 266Climatic factors, 267Field factors, 268Varietal factors, 268Harvesting, handling and preparation for storage, 269Time of harvest, 269Handling, 269Post-harvest treatments, 270The storage environment, 271Fresh produce, 271Low-temperature storage methods, 271Controlled atmosphere (CA) storage, 272Seeds, 273Trends in commercial storage, 274Non-commercial storage, 275Seeds, 275Soft fruits, 275Stone fruits, 275Pome fruits, 275Vegetables, 276Cut flowers, 276Conclusion, 276Further reading, 276Authors and affiliations, 27720 Garden ecology, 278Summary, 278Ecology and ecosystems, 278Ecology: open and closed systems, 278Food webs, 278Nutrient and carbon cycling, 279Cycling at the global scale, 280Habitats, 282Climate and soil tolerance, 282Natural processes and human land management, 283Slow-growing and fast-growing plants, 284Competition and herbivory, 286Habitat creation, 286Biodiversity, 288Why are there so many plants?, 288Diversity and stability, 289Ecological succession and the balance of nature, 289Unstable dynamics, 290Conclusions, 290Further reading, 291Authors and affiliations, 29121 Garden wildlife and conservation, 292Summary, 292Natives and aliens, 292Gardens and native flora, 292Native species and the Southwood hypothesis, 293Invasive plants and animals, 294Gardens and the wider environment, 295Wildlife in gardens, 295Ecosystem services, 296Conservation in gardens, 296Conservation of wild plants, 296Conservation of cultivars, 297Conclusions, 298Websites and further reading, 298Websites, 298Books, 298Authors and affiliations, 29822 Low-input and low-impact gardening, 299Summary, 299Introduction, 299Conservation of resources in the garden, 299Soil nutrients and organic matter, 299Water management, 300Recycling other materials, 302Wildlife, 302Carbon and greenhouse gas emissions, 304The problem of peat, 305Environmental footprint of lawns, 305Cash benefit of low-intensity garden management, 306Conclusions, 306Further reading, 306Websites, 306Books, 306Authors and affiliations, 30623 Health, well-being and socio-cultural benefits, 307Summary, 307Gardens and ecosystem service provision, 307Why garden?, 307Gardens and green therapy, 309Restorative landscapes, 313Horticultural therapy, 314Health risks, 315Crime and antisocial behaviour, 316Social and educational opportunities, 316Children and green space, 317Encouraging a balanced diet, 317Gardening and attitudes to the wider environment, 318Conclusions, 319Further reading, 319Author and affiliations, 31924 Gardens for science, 320Summary, 320Introduction, 320Botanic gardens, 320European origins and development in the United Kingdom, 320Collections, 322Research, 324Conservation, education and training, 325The gardens of horticultural societies, 325Private and small commercial gardens, 325Universities and independent research institutes, 326Conclusion, 328Further reading, 328Authors and affiliations, 328Glossary, 329Index, 355