This investigation seeks to elucidate the mechanism of carbohydrate allocation in source leaves of sugar beet subjected to water stress. Specifically, the study will determine the effect of cellular turgor on sugar efflux across the mesophyll plasmalemma. Under drought conditions, both osmotic adjustment and export compete for limited assimilate supply. Based on previous work and assuming the apoplastic sucrose loading postulate, sucrose release from mesophyll cells appears to be a potential site of control for carbon allocation in leaves. The role and nature of turgor effect on sugar transport across plasmalemma of isolated mesophyll cells will be investigated in vitro in relation to its effect on export and osmotic adjustment.%%% Plant response to water stress has serious economic consequences. This project will provide the basis for new fundamental information needed to identify control points, limiting steps and possible interventions to mitigate drought conditions in plants.***//
