Fig. 3.

Effect of anion channel inhibitors on Al-stimulated release of citrate in rice bean. Seedlings were exposed to 0·5 mm CaCl₂ solution (pH 4·5) containing 50 µm AlCl₃ in the presence or absence of each inhibitor (20 µm). Root exudates were collected after 9 h of treatment. Organic acids were analysed by HPLC. Error bars represent ± s.d. (n = 3).