Introduction

Abstract

The idea of a separate Encyclopedia volume dealing with the “interrelations of plant hormones with factors in the environment of the plant, and its organs and tissues” originated with N.P. Kefford, and we are most appreciative of the help and advice provided by Prof. Kefford in the formative stages of this volume. We have thus interpreted “environment” very broadly to include not only factors external to the plant, e.g., gravity, light, temperature, wind, mechanical wounding, water, organisms (including pollen), and magnetic and electric stimuli, but internal factors as well (e.g., nutrients, both inorganic and photoassimilate, direction, and time). In our definition of “hormonal effect”, or “hormonal involvement”, we have asked our authors to take a broad approach, and to examine not only phenomena that are mediated by the known plant hormones, but to discuss as well a wide variety of processes and events where hormonal involvement is implied through more indirect analyses and observations.