| Abstract: | The effects of 3 ? 10–2 mol m–3 FC on rubidium fluxesand contents in isolated guard cells of Commelina communis L.have been studied using 86RbCl. Fusicoccin causes a marked stimulationof influx and an immediate, apparently irreversible, decreasein efflux of 86Rb. The effect on influx is usually more importantin determining the new net flux of Rb. Observed fluxes differmarkedly from those predicted by the Goldman-Hodgkin-Katz equation,suggesting that FC does not act solely via an effect upon theplasmalemma potential. Fusicoccin appears to have a more directeffect upon the ion movements associated with changes in stomatalaperture than either ABA or transfer to the dark. Observed changesin Rb content cannot account fully for the osmotic changes associatedwith aperture increase. Key words: Fusicoccin, Guard cells, Ion fluxes, Commelina communis |
