Interpretation of Water Flow in Soil-Plant-Atmosphere System Based on Plant Water Environment

Abstract

Water flow in plants closely relates to various plant physiological activities. Nevertheless, most models of soil-plant-atmosphere continuum (SPAC) have been traditionally considered as a totally physical phenomenon. Recent findings in plant physiology have revealed that the stomatal control has nothing to do with the leaf water potential, but with the root signals that are produced at the condition of water deficit in roots. That is, several experiments have demonstrated the mechanism that hormon, like abscisic acid, transfered along with transpiring water flow acts guard cells to close stomatal openings when soil becomes dry. We suggested that this fact might greatly change the SPAC model in future, and discussed the remaining problems.