灌浆结实期不同时段温度对水稻结实与稻米品质的影响

利用人工气候箱在水稻灌浆结实期不同时段进行温度试验，研究温度对水稻结实与稻米品质的影响。结果表明，灌浆结实期40℃高温处理后籽粒结实率显著降低，粒重下降，外观品质和食味品质变差。不同水稻品种对灌浆结实期温度的响应表现不一致。在试验条件下，华粳1号开花受精的敏感温度为35℃，而特优559开花、灌浆结实的最适温度为30℃，该温度处理结实率、粒重较高，外观品质以及食味品质较优。此外，灌浆结实期不同时段的高温对水稻结实与稻米品质的影响也存在显著差异：结实率对高温最敏感的时期是开花后1~5 d，粒重对高温最敏感的时期是开花后11~20 d；而温度对稻米品质影响最大的时期主要在花后16~20 d，25 d后温度处理影响较小。因此，灌浆前期适宜的温度条件对水稻优质栽培意义重大。

Response of Seed-Setting and Grain Quality of Rice to Temperature at Different Time During Grain Filling Period

An experiment was conducted with two rice varieties Huajing 1 and Teyou 559 in plant growth chamber with four temperature treatments for each of six times during grain filling period to investigate the response of seed-setting and grain quality to temperature at different time during grain filling.Seed setting rate and grain weight descended significantly,and appearance and eating qualities were worse after exposure to high temperature(40℃)at the filling stage.Under the experimental conditions,the optimum diurnal air temperatures for high seed setting rate,grain weight and good qualities were 35℃ and 30℃ at the filling stage for Huajing 1 and Teyou 559,respectively.Moreover,the response of seed-setting and grain quality to temperature differed with the temperature treated time.The most sensitive time of seed setting rate and grain weight to high temperature was at 1-5th and 11-20th day after flowering.However,high temperature at 16-20th day after flowering produced the most inferior appearance and eating qualities.High temperature had slight effect on grain quality at the later grain-filling stage(25 days after flowering).Therefore,temperature conditions during grain filling is one of the most important agricultural factors affecting rice good quality production.