抄録
To elucidate the regulatory mechanisms of starch accumulation and key enzyme activities in rice grains under different cultivation methods in arid regions, this study selected four representative rice varieties and established three typical planting patterns: water-conserving dry direct seeding (W1), dry seeding followed by irrigation (W2), and traditional transplanting (W3). The yield components, grain starch content, and activities of key enzymes involved in starch synthesis, including AGP, GBSS, and SSS, were systematically analyzed. The results showed that, compared with W3, both W1 and W2 treatments slightly reduced total yield but significantly improved 1,000-grain weight and seed setting rate, and markedly increased total starch and amylose content in the grains, with the most pronounced effects observed under W1 treatment. Enzyme activity assays indicated that W1 and W2 significantly enhanced SSS activity, while W3 maintained higher AGP and GBSS activity. Significant varietal differences were observed in response to cultivation methods, with variety B performing best across multiple key traits. Further correlation analysis revealed significant positive relationships between starch synthase activity and starch accumulation, indicating that cultivation methods can influence starch composition and accumulation by modulating the expression and activity of related enzymes. This study reveals the physiological effects of different rice cultivation models on starch synthesis in arid regions, providing theoretical and practical guidance for optimizing dry direct seeding techniques and improving rice quality.
