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以耐阴性中等的杂交稻川香9838为材料,研究不同播期和抽穗期弱光胁迫对杂交稻抽穗期光合特征、渗透调节物质、保护性酶活性和产量的影响.结果表明:不同播期和抽穗期弱光胁迫对水稻抽穗期干物质积累、剑叶光合速率、抗氧化酶活性和产量均有显著影响.随播期的推迟,全生育期明显缩短,稻谷产量呈不同程度的下降趋势.与对照相比,抽穗期轻度弱光胁迫(遮光20%)能缓解水稻生育过程中面临的高温及强光照危害,进而能缓解剑叶光合速率和抽穗期干物质累积的降低,调节抗氧化酶活性,适度提高结实率;而抽穗期中度(遮光40%)、重度(遮光60%)弱光胁迫均不利于水稻生长.剑叶光合速率、丙二醛含量和超氧化物歧化酶活性对播期和抽穗期弱光胁迫较为敏感.水稻始穗1～5d剑叶光合速率与稻谷产量和抽穗后干物质积累量显著相关.
The effects of weak light stress at different sowing dates and heading stages on the photosynthetic characteristics, osmotic adjustment substances, protective enzyme activities and yield of heading date of hybrid rice were studied with medium-negative tolerant hybrid rice Chuanxiang 9838.The results showed that: And low light stress at heading stage had significant effects on dry matter accumulation, flag leaf photosynthetic rate, antioxidant enzyme activity and yield of rice at heading stage. With the delay of sowing date, the whole growth period was significantly shortened and the rice yield decreased in varying degrees Compared with the control, mild low light stress (20% shading) at the heading stage could alleviate the high temperature and the strong light hazard in the process of rice growth, and then alleviate the decrease of photosynthetic rate and dry matter accumulation at heading stage, Oxidative enzyme activity and moderately increased seed setting rate. However, medium intensity (shading 40%) and severe (shading 60%) weak light stress were not conducive to rice growth at heading stage.The photosynthetic rate, MDA content and superoxide dismutase activity Which was sensitive to low light stress at sowing and heading stage.The photosynthetic rate of flag leaf at 1 ~ 5 d after heading was significantly correlated with the rice yield and dry matter accumulation after heading.