Abstract

Water deficit affects plant growth and productivity and is the single most important factor limiting crop yields worldwide. To breed crops better able to cope with limited water availability we need to know how water moves through plants and mechanisms that control water transport. This entry provides a summary of our current understanding of these processes. It briefly describes the way in which water flows through plants and soils due to gradients in water potential. Mechanisms that improve the retention of water within the plant and ways that the plant can manipulate the flow of water are also described. An emphasis is given to crop plants because improvement in maintaining the hydration of crops is important for efficient agricultural water use and greater productivity.