Morphology, Physiology And Regulation In The Grain Formation Of Rice

It has great significance in understanding the mechanism in the formation of grain weight and quality of rice to elucidate the changes in the morphological structure, physiology and biochemistry of grains during the grain formation (the development and filling of a fertilized ovary). This study investigated the characteristics of grain formation and their differences among rice genotypes and grain positions within a panicle from the aspects of grain filling,endosperm development, kernel density, crystal percentage of endosperm starch and activities of the enzymes associated with starch synthesis. The effects of low and high temperatures at different grain filling stages, soil moisture and nitrogen (N) management on photosynthetic characters, endosperm development and grain quality were also investigated .The main results were as follows:1. Grain filling characteristics and endosperm structures of different rice genotypes With indica and japonica cultivars, including glutinous rice and hybrids, as materials, the differences in grain filling and the formation of endosperm structures among the genotypes were investigated. The results showed that (1) Grain filling rates varied significantly with rice genotypes,with the greatest for hybrids, the second for indica, and the least for Japonica. The grain-filling rate of glutinous rice was between indica and japonica. The earlier the spikelet flowered, the greater the mean and maximum grain filling rates, the shorter the active grain filling period and the time reaching the maximum grain filling rate, and the greater the grain weight. (2) The development of length and width for a superior grain, was completed about 15 days after...