Stress Interactions at the Cellular and Membrane Levels

In nature, plants are often exposed to several environmental stresses at any given time.For example, chilling or heat stress is often accompanied by water stress and, during winter, evergreens are often exposed to light (photo-oxidation) stress.Thus, to better-understand plant response to the environment under natural conditions, one must learn the mechanisms by which the plant adapts to, is injured by, and recovers from various environmental stresses.One approach to understand these interactions is to study the nature of stresses and stress-induced perturbations at the cellular and membrane levels.Membranes have been implicated as sites of response by various environmental stresses for a long time (see Levitt, 1980).However, only recently has the nature of these responses at the membrane level been studied.In this paper, I have attempted to synthesize the research, especially in the area of freezing stress.Research on membrane aspects is vast and beyond the scope of this paper.I have tried to focus on some key aspects of cell membranes (especially plasma membrane) important in the initiation and progression of injury.The present status of research is discussed to point out future directions of research that might bring better understanding of the interactions among various environmental stresses.