Effects of Growth Regulators on H+Translocation across the Membranes of Plasma Membrane Vesicles from Potato Tuber Cells

Effects of the growth regulators epibrassinolide-694 (EB), gibberellic acid (GA), and abscisic acid (ABA) on the ATP-dependent translocation of H⁺through the membranes of plasma membrane vesicles of potato (Solanum tuberosumL.) tuber cells were studied. The ATP-dependent accumulation of H⁺in the plasma membrane vesicles from dormant tubers was inhibited by EB and ABA and stimulated by GA. After the break of dormancy, the stimulatory effect of GA increased, the inhibitory effect of ABA decreased, and EB stimulated the accumulation of H⁺in the vesicles. The data suggest that the plasma membrane H⁺ATPase is a target of phytohormones that regulate the dormancy of potato tubers.