Abstract: | Clint, G. M. 1987. The effects of fusicoccin on anion fluxesin isolated guard cells of Commelina communis L.J. exp.BoL 38: 863876. The effects of 3?102 mol m3 fusicoccin (FC) onbromide fluxes and contents in isolated guard cells of Commelinacommunis L. have been studied using K82Br at pH 3?9 and pH 6?7.At pH 3?9 FC caused a reduction in both the influx and the effluxof 82Br, whereas at pH 6?7 FC had no effect on the influx butcaused a transient increase in the efflux of 82Br. There wasno obvious change in bromide content with FC treatment at eitherpH. The behaviour of the anion fluxes in response to FC suggeststhat FC does not act solely via a hyperpolarization at the plasmalemma.A redistribution of bromide between the intracellular compartmentssuggests that anion flux from the cytoplasm to the vacuole maybe stimulated by FC at pH 3?9. The failure of guard cells toincrease their anion content on treatment with FC despite anincrease in stomatal aperture and in cation content suggeststhat in FC-induced stomatal opening excess cation is balancedby organic acid synthesis within the guard cell. Key words: Fusicoccin, guard cells, ion fluxes, Commelina communis |