Patch clamping whole-cell reeording techniques were apphed to study the inward K+ channels in Arabidopsis root cortex cells. The inward K+-channels in the plasma membranes of the root cortex cell protoplasts were activated by hyperpolarized membrane potentials. The channels were highly selective tor K+ ions over Na+ ions. The channel activity was significantly inbibited by the external TEA（?） or Ba（?） The changes in cytoplasmic Ca2+ concentrations did not affect the whole-cell inward K+-currents. The possible asso（?）ation betw（?）en the channel selectivity to K+ and Na（?） ions and plant salt-tolerance was also discussed.
