THE EFFECT OF ALUMINUM ON MITOTIC-ACTIVITY AND LEVEL OF FREE CYTOKININS IN BARLEY (HORDEUM-VULGARE L) ROOTS

Mitotic activity in root apical meristem was negatively influenced by aluminium sulphate at low concentration (0.025 mu mol.l(-1)) and acid pH. The low concentration of aluminium sulphate in nutrition medium at pH 4.5 decreased the level of free endogenous cytokinins in young bar ley plants (Hordeum vulgare L.) as compared with the effect of pH 4.5 and 5.5. Different concentrations of A1(OH)(3) (3, 6, and 12 mmol.l(-1 ), respectively) and pH (5.5 control; 4.5 and 6.7) inhibited the mitot ic activity mainly at pH 6.7. Also the level of free cytokinins was de creased. The mitotic activity in root apical meristem correlated with the level of free endogenous cytokinins.