Water is essential for life and without water no life exists. The liquid sur rounding of an aqueous solution is the conditio sine qua non for most of the physiological responses and as such, water is as decisive for the occurrence of a single enzymatic reaction as it is for the global zonation of world vegetation. It is no wonder that scientists since early times have made every effort to describe and understand the functional interrelationships between water and the phe nomenon of life. During the past half of this century, these endeavours in the field of botany have been marked by steps which might be symbolized by a series of books such as "The plant in relation to water" (1. Maximov, 1929), and "Die Hydratur der Pflanze in ihrer physiologisch-6kologischen Bedeutung" (H. Walter, 1931), then "Pflanze und Wasser" (Vol. III of the Encyclopedia of Plant Physiology, edited by O. Stocker, 1956), and "Plant-water relations" (R. O. Slatyer, 1967), or the treatment of "Displacement of water and its control of biochemical reactions" (S. Levin. 1974).

Inhalt
1 Fundamentals of Plant Water Relations.- Preface.- A. The Structure of Water in the Biological Cell.- B. The States of Water in the PlantTheoretical Consideration.- C. The Soil-Plant-Atmosphere Continuum.- D. The Water Status in the PlantExperimental Evidence.- 2 Water Uptake and Soil Water Relations.- Preface.- A. Root Extension and Water Absorption.- B. Resistance to Water Flow in the Roots of Cereals.- C. Soil Water Relations and Water Exchange of Forest Ecosystems.- 3 Transpiration and Its Regulation.- Preface.- A. Energy Exchange and Transpiration.- B. Water Permeability of Cuticular Membranes.- C. Physiological Basis of Stomatal Response.- D. Current Perspectives of Steady-state Stomatal Responses to Environment.- E. Water Uptake, Storage and Transpiration by Conifers: A Physiological Model.- 4 Direct and Indirect Water Stress.- Preface.- A. Water Stress, Ultrastructure and Enzymatic Activity.- B. Water Stress and Hormonal Response.- C. Carbon and Nitrogen Metabolism Under Water Stress.- D. Water Stress During Freezing.- E. Cell Permeability and Water Stress.- F. Water Stress and Dynamics of Growth and Yield of Crop Plants.- 5 Water Relations and CO2 Fixation Types.- Preface.- A. Crassulacean Acid Metabolism (CAM): CO2 and Water Economy.- B. Balance Between C3 and CAM Pathway of Photosynthesis.- C. C4 Pathway and Regulation of the Balance Between C4 and C3 Metabolism.- D. Ecophysiology of C4 Grasses.- 6 Water Relations and Productivity.- Preface.- A. The Use of Correlation Models to Predict Primary Productivity from Precipitation or Evapotranspiration.- B. The Use of Simulation Models for Productivity Studies in Arid Regions.- C. Irrigation and Water Use Efficiency.- D. Estimating Water Status and Biomass of Plant Communities by Remote Sensing.- E. PlantProduction in Arid and Semi-Arid Areas.- F. Water Content and Productivity of Lichens.- 7 Water and Vegetation Patterns.- Preface.- A. Water Relations and Alpine Timberline.- B. The Water Factor and Convergent Evolution in Mediterranean-type Vegetation.- C. The Water-Photosynthesis Syndrome and the Geographical Plant Distribution in the Saharan Deserts.- Index of Plant Species.