Abstract
The purpose of the present paper is to identify morphological and physiological traits of acid soil tolerant varieties of rice plants (Oryza sativa L.) in Narathiwat Province of Southern Thailand where the yield reduction of rice plants due to acid soil is markedly severe. Six tolerant varieties selected from 48 grown under artificially prepared acid soil (pH 4.0) for 4 weeks after transplanting, and 3 intolerant varieties as a control were used in the present study. Tolerant varieties had longer roots and a larger leaf area than intolerant varieties in acid soil conditions. Aluminum (Al) concentration in the leaves was significantly lower in tolerant varieties than in intolerant varieties. Leaf photosynthesis (LPS) of tolerant varieties was significantly higher than that of the intolerant varieties in acid soil conditions. These results indicate that transportation of Al from the root to the leaf is prevented by some mechanism in the tolerant varieties, which may be a mechanism of acid soil tolerance.
