关键词: 杂交水稻, 常规水稻, 粳稻, 灌浆, 叶片, 光合特性, 叶绿素荧光特性

Abstract: The grain filling processes of late japonica hybrid and conventional rice cultivars from southern China were analyzed with the Richards’ growth equation,as well as the leaf photosynthesis and chlorophyll fluorescence characteristics at late growth stage.Hybrid rice combination Xiuyou 5 showed slightly lower initial grain filling potential,maximum grain filling rate and mean grain filling rate than the conventional rice cultivar Xiushui 110,but longer active grain filling duration,contributing to get heavier grain weight and to cut down the competition for assimilate among grains per panicle.The differences in leaf photosynthesis and chlorophyll fluorescence parameters were not significant between Xiuyou 5 and Xiushui 110 at 10 d after flowering.However,Xiuyou 5 had significantly higher leaf photosynthesis and chlorophyll fluorescence parameters than Xiushui 110 at 25 d after flowering,except for the unquenchable portion of fluorescence.It is suggested that maintaining higher leaf biomass production capacity at late grain filling stage is a very important physiological mechanism for late japonica hybrid rice,resulting in longer active grain filling duration,and finally a relative better grain filling,heavier grain weight and higher grain yield despite the larger number of spikelets per panicle.

Key words: hybrid rice, conventional rice, japonica rice, grain filling, leaf, photosynthesis characteristic, chlorophyll fluorescence characteristic