ABA depolarizes guard cells in intact plants, through a transient activation of R- and S-type anion channels.

摘要: Summary During drought, the plant hormone abscisic acid (ABA) induces rapid stomatal closure and in turn reduces transpiration. Stomatal is accompanied by large ion fluxes across plasma membrane, carried K+ anion channels. We recorded changes activity of these channels induced ABA, for guard cells intact Vicia faba plants. Guard their natural environment were impaled with double-barrelled electrodes, ABA was applied via leaf surface. In 45 out 85 tested, triggered a transient depolarization membrane. cells, membrane potential partially recovered presence ABA; however, full recovery potentials only observed after removal ABA. Repetitive responses could be evoked single but magnitude response varied from one application to other. The correlated activation channels, which peaked 5 min introduction stimulus. moderate increase conductance (ΔG   5 nS), activated voltage-dependent (rapid (R)-type) addition S-type conclude that combined two channel types leads cells. nature this correlates extrusion Cl− confined reduction aperture.