CHANGES OF H-VIVO AND IN-VITRO UNDER ALUMINUM TREATMENT AND EFFECT OFCALCIUM( PUMPS OF TONOPLAST VESICLE FROM WHEAT ROOTS IN)

Wheat seedlings were treated with 0.1 mM Al for 7 days. Tonoplast vesi cles were isolated from apical segments of roots and activities of H+- ATPase and H+-PPase measured. Compared with the control, 0.1 mM Al inc reased H+-ATPase activity and decreased H+-PPase activity. High extern al supply of calcium (Ca) (5 mM) diminished the extent of the stimulat ion of H+-ATPase activity and alleviated the reduction of H+-PPase act ivity under Al treatment. However, 0.1 mM Al treatment in vitro result ed in the inhibition of H+-ATPase activity with the decrease of Vmax a nd Km for ATP. In vitro treatment with 0.1 mM Al also decreased the H-PPase activity, but increased the Km for PPi.