Charles Y. Sullivan

Plant Physiological Responses to Water Stress

Factors involved in physiological responses to water stress are discussed as they may relate to water-use efficiency by plants grown under conditions of drought. Evidence is presented that genotypic differences exist in plant responses to water stress. It is shown that previous exposure to stress conditions, or a natural hardening period, can markedly influence measured responses, such as photosynthesis and stomatal movement. Stage of growth at which the stress occurs also influences the response. A practical technique for measuring desiccation and heat tolerance demonstrates that genetically controlled tolerance factors can be selected for and used in plant breeding programs.