Aluminum effects on the growth and mineral composition of corn plants cultivated 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) activity to investigate the Al toxicity effects on their growth and mineral nutrition. With increasing levels of Al in the nutrient solution, root growth and root dry weights decreased for both cultivars, while higher reductions were found for 'HS7777'. The concentrations of nitrogen (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 cultivars. This increase of Al toxicity increased the concentrations of carbon (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'.