Abstract: Using 6 mid-maturing lowland and upland rice varieties as materials, the characteristics of photosynthetic rate and matter translocation were studied. The photosynthetic rate of the leaves declined with the decrease of soil water potential, but drought-resistant varieties reduced less than drought-sensitive ones. The decline of photosynthetic rate at the community level mainly resulted from reduced leaf area after a long time treatment of low soil moisture. The treatments of low soil moisture caused the increase of sucrose and total soluble sugars, and the decrease of starch in the leaves. Starch/soluble sugars ratio and starch/sucrose ratio very significantly correlated with the relative yield (the treatment/the control, r= 0. 9854 and 0. 9412, respectively). The accumulation of usable sugars (soluble sugars+starch) in the stems and sheaths at heading decreased, and the translocation of the usable sugars after heading increased under the treatments of low soil moisture. Relative values of the accumulation for drought-resistant varieties were greater than those for drought-sensitive ones. However, it seemed that the ability of remobilization was not related to the drought resistance of a variety.

Key words: drought-resistance, matter translocation, photosynthetic rate, soil moisture

摘要： 以6个中熟水、陆稻品种为材料，研究了在不同土壤水分状况下水稻光合速率与物质运转的特点。叶片光合速率随土水势的下降而减小，抗旱性品种减小的幅度小于抗旱性较差的品种。长期低土壤水分处理后，群体光合能力的下降主要是由于叶面积的减小。低土壤水分处理导致叶片中蔗糖和总可溶性糖含[CM(45*2]量的增加，淀粉含量的减少。淀粉/可溶性糖、淀粉/蔗糖与相对产量(处理/对照)呈极显著正相关(r=0.9854、 r=0.9412)。低土壤水分处理下，抽穗期茎鞘中可用性糖(可溶性糖+淀粉)累积量减少，抽穗后运转率增加，抗旱性品种的相对累积量(处理/对照)高于抗旱性较差的品种，但运转率的大小与品种的抗旱性无明显联系。

关键词: 土壤水分, 光合速率, 物质运转