Abstract: In order to reveal the influence law of night temperature rise on the physiological process of grain filling during the filling process, the temperature change in the natural environment was simulated by using the climate chamber, and three different night temperature treatments, 21℃ (T1), 25℃ (T2) and 29℃ (T3), were set up in the three stages of rice filling process, which were P1 (the first 10 d after rice flowering), P2 (11~20 d after rice flowering) and P3 (21~30 d after flowering), and in the meantime, the highest temperature of daytime is 32℃. The effects of night temperature rise in different filling periods on the contents of grain starch and sucrose and their metabolism-related enzyme activities were studied during rice filling. The results showed that the activities of starch and sucrose metabolism-related enzymes of rice grains in P1 and P2 periods after rice flowering were significantly affected by the increase of night temperature, among which P1 period was the most sensitive period for starch metabolism to the change of night temperature. At the early stage of filling（P1）, the content of starch increased significantly with the increase of night temperature, as well as the contents of amylose and amylopectin, while the content of sucrose decreased. Under the same condition, the activities of sucrose synthase, soluble starch synthase and starch branching enzyme decreased, and the activities of sucrose phosphate synthase increased during the daytime and decreased at night. This indicated that the increase of night temperature had a sustained effect on the enzyme activity, that was, the enzyme activity during daytime was also affected by the increase of night temperature. The results provided a reference for understanding the influence mechanism of climate change on grain material accumulation during rice grain filling.

Key words: rice, night temperature rise, grain filling, starch, enzyme activity

摘要： 为了揭示夜间温度升高对灌浆过程中籽粒灌浆生理过程的影响规律，采用人工气候箱模拟自然环境的温度变化，在水稻灌浆的3个时期P1（水稻开花后的前10 d）、P2（水稻开花后11~20 d）和P3（水稻开花后21~30 d），均设置21℃（T1）、25℃（T2）和29℃（T3）3种不同的夜间温度处理，日间最高温度为32℃，研究水稻灌浆期间，不同灌浆时段夜温升高对水稻籽粒淀粉和蔗糖含量及其代谢相关酶活性的影响。结果表明，水稻开花后的P1时期和P2时期籽粒淀粉和蔗糖代谢相关酶活性受夜温升高的影响较大，其中P1时期是淀粉代谢对夜温变化最敏感的时期。灌浆初期（P1），夜温升高，淀粉含量显著上升，直链淀粉和支链淀粉的含量也随之上升，蔗糖含量下降；蔗糖合成酶、可溶性淀粉合成酶和淀粉分支酶活性下降，蔗糖磷酸合成酶日间酶活性上升而夜间下降，这说明夜温升高对酶活性的影响具有持续效应，即日间酶活性也会受到夜温升高的影响。研究结果为明确水稻籽粒灌浆过程中气候变化对籽粒物质积累的影响机制提供了参考。

关键词: 水稻, 夜温升高, 籽粒灌浆, 淀粉, 酶活性