杂种稻在不同温度条件下的光合适应性和光合生产力的研究

Adaptability and Productivity of Photosynthesis in Hybrid Rice under Different Temperatures

在人工气候箱控温条件下比较了杂种稻Ｌｅｍｏｎｔ／七桂早（Ｌｅ／七）及其亲本Ｌｅｍｏｎｔ和七桂早对短期高温及中温处理条件下的光合适应性和光合生产力．当早稻试验植株从室外平均高温２９．４℃移至箱内经４１℃处理３ｈ后，七桂早及Ｌｅｍｏｎｔ两个亲本的单叶净光合速率下降了８０％左右，而杂种稻Ｌｅ／七只下降了约５０％，表现了较强的抗“高温＋中等强光”所引起的光抑制伤害．Ｌｅ／七的作物生长率（ＣＧＲ）及总生物量，无论在早季或晚季，无论在高温或中温处理条件下，都比双亲明显为高．结合以前关于高低光强适应性试验结果综合分析。可以认为由于光合作用的杂种优势，Ｌｅ／七在光合适应性及光合生产力方面均比亲本有了明显的提高．

Hybrid rice Lemont/Qiguizao(Le/Qi) and its parents, the female one from United States of America, and the male one from South China, were studied buder controlled short-term high and moderate temperature in growth chambers to compare their photosynthetic adaptability and productivity. Afler short-term treatment with 41 t (3h), which was 12℃ higher than normal atmospheric high temperature, with light intensity of 650 μmol photons m-2s-1 in early rice in growth chamber, the Pn of all plants were remarkably decreased.Qiguizao and Lemont reduced about 80% of normal Pn, but hybrid Le/Qi only reduced by 50% of normal Pn,showing higher tolerance to the photoinhibition damage caused by suddenly raising temperature with middle high light intensity. The CGR and biomass of Le/Qi were also remakably higher than that of both Qiguizao and Lemont under both high and moderate temperatures. This study and our previous relevant studies on hybrid Le / Qi and its parents, especially to the Qiguizao,show that the utilization of photosynthetic heterosis in the cross of two different light intensity ecotypes of rice is a promising breeding approach to enhancing photosynthctic productivity and wider adaptability.