中文摘要：

以耐热性不同的2个水稻品系为材料,研究了花后不同时段高温对水稻籽粒充实的影响。结果表明,花后不同时段高温条件下,水稻籽粒千粒重和充实度降低,且随胁迫时间延长下降幅度增大,热敏感品系4628籽粒千粒重和充实度的下降幅度大于耐热品系996。高温胁迫下种子可溶性糖、蔗糖和ABA含量增加,但随着胁迫时间延长呈现降低趋势,而高温下淀粉积累减少。高温胁迫下水稻种子发芽势、发芽率、发芽指数和活力指数下降,热敏感品系4628的下降幅度均大于耐热品系996;花后高温条件下,籽粒胚乳淀粉粒排列结合较为疏松,淀粉粒间空隙大,多为单粒淀粉体,导致籽粒充实不良。

英文摘要：

The experiment was carried out in growth chamber to investigate the effect of high temperature at different time after anthesis on grain plumpness of two rice（Oryza sativa） lines including the heat-tolerant line 996 and heat-sensitive line 4628. The results showed that 1 000 grain weight and grain plumpness was reduced under high temperature at different time after anthesis, and the decrease extent was increased with the increase of stress time, the reduced range of heat-sensitive line 4628 was greater than that of heat-tolerant line 996. The soluble sugar, sucrose and ABA contents increased under high temperature stress, and then decreased with the increase of stress time, while starch accumulation decreased under high temperature. The germination rate, germination potential, germination index and vigor index of rice seeds were decreased under high temperature, the reduced range of heat-sensitive line 4628 was greater than that of heat-tolerant line 996. Under high temperature at different time after anthesis, starch granule had an incompact arrangement, most of the starch granule existed in the form of a single starch endosperm, and led to poor grain filling.