Proton-Chloride Symport in Barley Roots

An increase in the acidity of the incubation medium from pH6 5 to pH 4.0 increased Cl- flux into ATP-depleted Hordeum vulgareL roots more than three times This pH-dependent Cl^– fluxwas inhibited by p-chloromercuriphenyl sulphonic acid. The effectof pH on Cl- influx was eliminated when the pH gradient wasdissipated by addition of salts of permeable weak acids, andin K-loaded roots in the presence of a protonophore togetherwith valinomycin The results support the assumption that a H⁺-Cl^–symportsystem is present in barley root cells Hordeum vulgare L., barley, excised roots, ion transport, proton-chloride symport