Induction of Aluminum Tolerance in Wheat Seedlings by Low Doses of Aluminum in the Nutrient Solution

Preincubation of wheat (Triticum aestivum L. Thell.) seedlings in a nutrient solution containing low doses of aluminum (0.5 microgram per milliliter for tolerant cultivar Atlas 66 and 0.1 microgram per milliliter for the sensitive cultivar Grana) enabled substantial root regrowth of varieties grown in a lethal aluminum concentration, despite an increased accumulation of aluminum in root tissue of the pretreated seedlings. The distribution of aluminum in the subcellular fractions remained unchanged. The increase in tolerance was completely abolished by the addition of cycloheximide. Aluminum ions at sublethal concentrations significantly increased the incorporation of [(14)C]valine and [(3)H]thymidine in roots. The possible role of the synthesis of the inducible aluminum binding protein in the mechanism of aluminum tolerance is discussed.