ALUMINUM EFFECTS ON THE GROWTH AND MINERAL-COMPOSITION OF CORN PLANTSCULTIVATED IN NUTRIENT SOLUTION AT LOW ALUMINUM ACTIVITY

Two cultivars of corn (Zea mays L., 'HS7777' Al-sensitive and 'C525-M' Al-tolerant) were grown in nutrient solution at low aluminum (Al) act ivity to investigate the Al toxicity effects on their growth and miner al nutrition. With increasing levels of Al in the nutrient solution, r oot growth and root dry weights decreased for both cultivars, while hi gher reductions were found for 'HS7777'. The concentrations of nitroge n (N), calcium (Ca), magnesium (Mg), potassium (IC), and manganese (Mn ) in the shoot and roots and iron (Fe) and zinc (Zn) in the shoot only decreased with the increase of Al levels in solution for both cultiva rs. This increase of Al toxicity increased the concentrations of carbo n (C), copper (Cu), and boron (B) in the shoot and C, P, Fe, and Cu in the roots for both cultivars. High average concentrations of Ca, Mg, Mn, and Cu were found in the shoot of 'HS7777'. No differences in the concentrations of Al, Ca, Mg, P, and Mn were observed in the roots of the two cultivars. Aluminum concentrations were considerably higher in the roots than in the shoot, although lower Al concentrations in the shoot were found for 'C525-M'.