Figure 5.

Effects of various Al concentrations (0, 2.5, 5 and 10 µM) in vitro on the relative H⁺-ATPase activity in PM vesicles isolated from the roots of ET8 (A) and ES8 (B). Seedlings were grown in Al-free 0.2 mM CaCl₂ solution, adjusted to a pH of 4.5 for 5 days after germination. The PM vesicles were isolated from the root tips (0–10 mm) and the region distal to the tip (10–20 mm). Five µg of the PM protein (pH 7.4) was then treated with various concentrations of Al for 10 min in vitro, and centrifuged for 1 hour at 100,000 g in order to minimize the carryover of Al from the treatment solution. This experiment was conducted three times, and values from representative experiments are expressed as means ± SE (n = 3). Asterisks indicate statistically different means (*p < 0.05, Student's t-test). (From ref. 35).