Stomatal Movement and Sucrose Uptake by Guard Cell Protoplasts of Commelina benghalensis L.

Sucrose concentration in guard cells of epidermal strips of Commelina benghalensis increased with stomatal opening. Sucrose uptake patterns were investigated using guard cell protoplasts of C. benghalensis. Sucrose (0.5 mM) uptake into these protoplasts was sensitive to pH, with an optimum at pH 6. Uptake of sucrose into guard cell protoplasts was inhibited by 2,4-dinitrophenol (DNP), diethylstilbestrol (DES) and (ptrifluoromethoxy)carbonyl cyanide phenylhydrozone (FCCP), while DCMU and o-phenanthroline had no effect on the uptake of sucrose. Fusicoccin (FC) stimulated sucrose influx. The influence of pH and the effect of the metabolic inhibitors on the sucrose uptake into the guard cell protoplasts are consistent with an energy dependent membrane-function.