抄録
Rice is the most Al-tolerant species among small-grain cereal crops, but the mechanisms responsible for high Al tolerance are unknown. We have isolated two Al-sensitive rice mutants (als1 and als2). Here, we report a novel rice mutant (c68) sensitive to Al. This mutant was isolated from 1170 M2 lines, which are derived from an Al-tolerant cultivar (Koshihikari) irradiated with γ-rays. Physiological studies showed that this mutant was not only sensitive to Al, but also sensitive to other metals including Cd and La. Morphological and histochemical observations showed that the mutant had less number of root hairs and that exodermal cells were partially changed to sclerenchyma cells. Genetic analysis showed that they were controlled by a single recessive gene. These results suggest that the increased sensitivity to metals in the mutant is caused by alternation of root structure. The responsible gene was mapped on the short arm of rice chromosome 2.
