Energy Exchange and Transpiration

Water loss from a plant leaf is a process involving physical mechanisms and biological properties of the leaf. In principle, transpiration is a simple process, but in actuality it is an extremely complicated phenomenon because of the complexities of leaf properties and behavior. It is clear that certain conditions must exist for water to be transpired from a leaf to the environment. Water must be available, energy must be available in order to convert liquid water to vapor, and there must exist a water vapor gradient from inside to outside the leaf which drives the gas diffusion process. A review of earlier research concerning transpiration and leaf temperatures was given by Gates (1968).