Identification and characterization of inward K+-channels in plasma membranes of Arabidopsis root cortex cells

Patch clamping whole-cell recording techniques were applied to study the in ward K+-channels in Arabidopsis root cortex cells. The inward K+-channels i n the plasma membranes of the root cortex cell protoplasts were activated b y hyperpolarized membrane potentials. The channels were highly selective fo r K+ ions over Na+ ions. The channel activity was significantly inhibited b y the external TEA(+) or Ba2+. The changes in cytoplasmic Ca2+ concentratio ns did not affect the whole-cell inward K+-currents. The possible associati on between the channel selectivity to K+ and Na+ ions and plant salt-tolera nce was also discussed.