Chapter 1 - Introduction

Abstract

This introductory chapter focuses on physiological processes that regulate growth. Trees and shrubs are enormously important as sources of products, stabilizers of ecosystems, ornamental objects, and ameliorators of climate and harmful effects of pollution, erosion, flooding, and wind. Woody plants are subjected to multiple abiotic and biotic stresses that affect growth by influencing physiological processes. Environmental stresses set in motion a series of physiological disturbances that ultimately adversely affect growth. Appropriate cultural practices increase growth by improving the efficiency of essential physiological processes. Physiological processes are the critical intermediaries through which heredity and environment interact to regulate plant growth. The growth of plants requires absorption of water and mineral nutrients; synthesis of foods and hormones; conversion of foods into simpler compounds; production of respiratory energy; transport of foods, hormones, and mineral nutrients to meristematic sites; and conversion of foods and other substances into plant tissues. Knowledge of physiology of woody plants is useful for coping with many practical problems. These include dealing with poor seed germination, low productivity, excess plant mortality, potential effects of increasing CO2 concentration and global warming, environmental pollution, loss of biodiversity, plant competition and succession, and control of abscission of vegetative and reproductive structures. Useful application of knowledge of the physiology of woody plants is favored by recent improvements in methods of measuring physiological responses. Research employing electron microscopy, molecular biology, isotopes, controlled-environment chambers, and new and improved instruments including powerful computers, is providing progressively deeper insights into the complexity and control of plant growth. These developments should lead to improved management practices in growing forest, fruit, and shade trees.