Effect of auxin, gibberellin and kinetin on membrane potential and proton pump in wheat coleoptile cells

Abstract

The changes in the electric potential differences between the vacuole and the external medium, induced by IAA, GA3 and kinetin in wheat coleoptiles were investigated in relation to the acidification of the external medium brought about by these growth regulators. IAA caused a greater hyperpolarization of the membrane potential and larger enhancement of the proton pump as compared with GA3, whereas kinetin exerted no effect. Ouabain partly reversed IAA-induced hyperpolarization, this suggesting that ATPase might be involved in the action of IAA on son transport processes.

Keywords

• auxin
• gibberellin
• cytokinin
• proton pump
• membrane potential