Preface Science and the Garden has been written primarily for students of horticulture, but we expect that it will also be of interest to amateur gardeners and professional growers who would like to understand more about the science that underlies horticultural practices. Most conventional gardening books concentrate on how and when to carry out horticultural tasks such as pruning, seed sowing and taking cuttings. In contrast, the aim of the present book is to explain in straightforward terms some of the science that underlies these practices. We address such diverse questions as: why are plants green? Why should one cut beneath a leaf node when taking cuttings? Why do plants need so much water? Why is light so important and what effect does it have on plant growth? How do plants detect drying soils and how is growth modified to improve their survival chances? Why are plants more resistant to freezing in the autumn than in spring? How do plants detect seasonal changes in their environment? Why do chrysanthemums flower in the autumn and onions produce their bulbs in the summer? The first part of the book is concerned with some fundamental principles. Chapter 1 describes the structural features of the plant, and introduces biochemical and physiological processes such as photosynthesis and water and solute transport, which are expanded on in later chapters in relation to particular aspects of horticultural practice. Chapter 2 introduces the often difficult question of how plants are named. Plant names are a problem for many gardeners and this chapter explains the structure of plant nomenclature in simple terms; it outlines the rules for naming plants, discusses why names sometimes change and, most importantly for the gardener,
what is being done to achieve stability in plant nomenclature. It is often thought that genetic modification (GM) is the 'new' thing in horticulture, but the fact is that most plants grown in gardens (except weeds) have been genetically manipulated in the sense that their genes differ from those of their wild relatives. 'Designing Plants' (Chapter 3) explains how new plants have been developed through cross-breeding and selection processes that have been going on for centuries. The chapter concludes with a look towards the future by showing how new plants can be 'designed' by introducing specific genes using GM technology. The remainder of the book is more immediately concerned with the practices of horticulture. With the exception of a few aquatics, gardening depends on the soil and Chapter 4 describes the different types of soil, explains how to recognise them and introduces the science underlying soil management practices. Water conservation is an important consideration in many gardens and may well become more important with climate change. The selection of suitable plants is itself a form of water conservation by the gardener and Chapter 5, 'Choosing a Site', describes how certain plants are adapted to grow in dry conditions. All gardens have shady areas and Chapter 5 also explains how plants are able to detect shade from trees and neighbouring buildings and modify their growth accordingly. It ends with advice on how to choose plants for particular situations using scientific principles. 'Raising Plants from Seed' (Chapter 6) and 'Vegetative Propagation' (Chapter 7) are basic horticultural practices. These two chapters discuss the science underlying embryo development, seed maturation and ripening, dormancy and how it may be broken, and the storage of seeds. They ix