关键词: 水稻, 夜温升高, 籽粒灌浆, 淀粉, 酶活性

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