The Biology of Horticulture

PART 1 HORTICULTURAL BIOLOGY 1 1 INTRODUCTION 3 Horticulture Defined 4 History of Horticulture 6 2 PLANT CLASSIFICATION 13 Early Classification Systems 13 Botanical Classification/Taxonomy 14 Horticultural Classification 18 References 22 3 PLANT STRUCTURE 23 The Cell 23 Organs 30 Flowers 49 Fruits 57 References 63 4 PLANT GENOTYPE 65 Genetic Improvements 66 Genetic Terminology 67 Fertilization 74 Heritability 74 Cloning Plants 77 Plant Breeding 79 Molecular Biology 81 Cross-Fertilization 83 Mutations 86 Pest Resistance 91 Summary 93 References 93 PART II THE AMBIENT ENVIRONMENT 95 5 LIGHT 97 Photosynthesis 99 Spacing and Orienting Plants for Light Interception 103 Etiolation 109 Effect of Pigments 113 Photoperiodism 120 Light Quantity and Plant Growth 127 Light Sources and Their Use 133 Systems for Measuring Light 136 Summary 139 References 139 6 TEMPERATURE 141 Temperature and Plant Growth 142 Sugar and Starch Conversions 147 Soil Temperature 149 Temperature Monitoring and Control 154 Cooling Controlled Environments 155 Heating and Energy Conservation in Controlled Environments 160 Temperature and Site Selection 166 Vernalization 168 Dormancy 169 Temperature Stress 172 Low-Temperature Effects 172 High-Temperature Effects 183 Temperature Fluctuations 185 Summary 186 References 186 PART III THE RHIZOSPHERE (ROOT ZONE) 187 7 WATER 189 Properties of Water 190 Horticultural Applications and Water Management 198 Irrigation 204 Timing and Amount of Water 218 Soil Moisture Measurement 220 Summary 226 References 226 8 SOILS AND SOIL MANAGEMENT 229 Characteristics of Soil 230 Aeration and Drainage 239 References 249 9 MINERAL NUTRITION 251 Early Knowledge of Essential Elements 251 Mineral Nutrient Uptake 252 Carbon, Hydrogen, and Oxygen 256 Macronutrients 257 Micronutrients 259 Fertilizer Practices 261 Fertilizer Sources 266 Inorganic Fertilizers 270 Fertilizer Application Methods 273 References 279 10 MULCHES 281 Advantages of Mulches 282 Use of Organic Mulches 282 Winter Mulching 284 Nonorganic Mulches 285 Limitations of Mulching 290 Summary 291 References 291 PART IV PLANT GROWTH SUBSTANCES 293 11 PLANT HORMONES 295 Major Plant Hormones 297 Growth-Promoting Hormones 297 Wounding and Stress Hormones 297 Growth-Promoting Hormones: Auxins 298 Gibberellins 304 Cytokinins 307 Brassinosteroids 311 Wounding and Stress Hormones: Ethylene 311 Abscisic Acid 315 Jasmonates 316 Other Plant Growth Substances 317 References 317 12 CHEMICAL CONTROL OF PLANT GROWTH 319 Dormancy 320 Apical Dominance 322 Apical Dominance 323 Growth Retardation 324 Vegetative Growth Promotion 326 Flowering 326 Sex Expression 328 Fruiting 329 Abscission and Harvest Aids 332 Summary 334 References 334 PART V HORTICULTURAL PRACTICES 335 13 PRUNING 337 Pruning 337 Summary 345 References 345 14 PLANT PROPAGATION 347 Vegetative Propagation 349 Cutting Propagation 349 Cutting Types 356 Layering 359 Specialized Plant Structures 360 Grafting and Budding 361 Micropropagation 364 Seed Propagation 368 Hardening-Off 376 Summary 377 References 377 15 POSTHARVEST HANDLING 379 Quality and Maturity 380 Biological Factors Involved in Deterioration 385 Environmental Factors Influencing Deterioration 387 Food Safety 389 Harvesting 390 Preparation for Market 391 Storage 397 Keys to Successful Handling of Horticultural Crops 403 References 405 Internet Resources 407 PART VI PLANT PROBLEMS 409 16 PLANT PESTS AND OTHER PROBLEMS 411 Plant Diseases 413 Fungi and Fungal-Like Organisms 416 Deuteromycetes or Fungi Imperfecti 425 Bacteria 425 Mollicutes (Phytoplasmas and Spiroplasmas) 427 Viruses and Viroids 427 Parasitic Higher Plants 430 Nematodes 431 Horticultural Practices and Plant Disease 432 Insects 432 Types of Insect Damage to Plants 437 Mites 445 Snails and Slugs 446 Vertebrate Pests 447 Weeds 450 Organic Approaches to Pest Management 453 Safety in the Use of Pesticides 454 Summary 455 References 455 APPENDIX 457 SCHEDULE A Field-Grown Processing Tomato (Lycopersicon esculentum) 458 SCHEDULE B Greenhouse-Grown Poinsettia (Euphorbia pulcherrima) 460 SCHEDULE C Balled and Burlapped Spreading Yew (Taxus cuspidata) 464 SCHEDULE D Apple, a Temperate Tree Fruit (Malus pumila) 466 SCHEDULE E Orange, a Subtropical Tree Fruit (Citrus sinensis) 470 SCHEDULE F Kentucky Bluegrass Sod (Poa pratensis) 474 Glossary 477 Index 493