PHYTOHORMONE EFFECTS ON HYDROLYTIC ACTIVITY OF PHOSPHOHYDROLASES IN RED BEET (BETA-VULGARIS L) TONOPLASTS

The effects of indole-3-acetic acid (IAA), abscisic acid (ABA), gibber ellic acid (GA(3)) and kinetin on the hydrolytic activity of proton pu mps (adenosine triphosphatase, H+-ATPase, pyrophosphatase, H+-PPase) o f tonoplasts isolated from stored red beet (Beta vulgaris L. cv. Bordo ) roots were studied. Results suggest that the phytohormones can regul ate the hydrolytic activities of H+-ATPase and H+-PPase of the vacuola r membrane. Each of the proton pumps of the tonoplast has its own regu lators in spite of similar localization and functions. IAA and kinetin seem to be regulators of the hydrolytic activity for H+-PPase whereas for H+-ATPase it may be GA(3). Stimulation of enzyme activity by all hormones occurred at concentrations of 10(-6) to 10(-7) M.