Selectivity of the Fast Activating Vacuolar Cation Channel

J. Exp. Bot. 50 (335): 873-876 (1999)

Brüggemann, L.I., Pottosin, I.I. and Schönknecht, G.

The FV channel dominates the ion conductance of the vacuolar membrane at physiological Ca²⁺ concentrations. Patch-clamp measurements on whole barley (Hordeum vulgare) mesophyll vacuoles and on excised tonoplast patches showed small differences in a selectivity sequence NH₄⁺ > K⁺ >= Rb⁺ >= Cs⁺ > Na⁺ > Li⁺. Less permeant cations decreased the open probability. The FV channel allows the uptake of small monovalent cations especially NH₄⁺ into the vacuole.