Effects Of Panicle Nitrogen Fertilizer On Grain Filling Of Caryopsis Flowering Different Time Of Rice

Grain filling of superior and inferior grains had been a hot topic of study for rice. The bad filling of inferior grains was one of the important reasons to decrease the seed setting rate and grain weight, especially too many empty and unfilled grains formed on cultivars characterized by a larger panicle type. There were many environmental factors involved in grain filling process, and the mechanism is complex. In-depth investigating the substance of the grain was helpful to deepen the scientific theory of crops during the grain filling process, and to improve the yield and quality of rice with important theoretical guidance and practical significance. Two different rice cultivars, Wuyunjing23and Wuyujing3, characterized by the significantly different number of grains per panicle and complemented by different levels of panicle nitrogen fertilizer fertilizer, were used in the experiment to analyze the accumulating changes of soluble starch and crude protein in brown rice with different flowering sequence. And in fresh grains differed by flowering sequence, the contents of endogenous hormones were investigated at the same time, while starch granule and protein bodies in endosperm were observed. Consequently, the effects and physiological mechanism of flowering sequence and panicle nitrogen fertilizer on grain filling of rice were aimed to be clarified and to provide a theoretical basis for the yield and quality improvement of rice. The main results were as follows:1. Effects were clarified of panicle nitrogen fertilizer on dry matter accumulation of caryopsis flowering different sequence during grain filling. The result showed that, caryopsis flowering earlier on the same rice spikelets had a faster grout starting, start potential was large, filling rate was higher, filling peak came earlier, active filling period was shorter, seed setting rate and grain weight was higher; caryopsis flowering later behaved in the rather opposite, especially in the peak filling rate, peak filling time and active grain filling stage, and ultimately setting rate and grain weight was significantly lower than caryopsis flowering earlier. The application of panicle nitrogen fertilizer significantly reduced spikelet filling rate and grain weight, expanding the early and caryopsis flowering late between the filling rate, filling peak, active filling stage and grouting termination values and other differences, filling rate of caryopsis flowering later lower peak filling later, active filling period is longer, lower seed setting rate and grain weight. Panicle without nitrogen application conditions, the first flowering spikelets5d1d than the first flowering spikelets started filling potential decline0.7-1.0mg·grain-1, the average filling rate decreased0.46mg-grain-1·d-1so, peak filling postpone6-14d and active filling period extended23-27d; panicle at high nitrogen (210kg N/hm2) levels were down0.4-2.2mg·grain-1, reduced0.52mg-grain-1·d-1about delayed13-15d and extend31-36d. Wuyunjing23and Wuyujing3basically the same performance.2. Clearing effects of panicle nitrogen fertilizer on soluble sugar, starch and protein accumulation in caryopsis flowering different sequence during the grain filling. In the same rice spikelet, soluble sugar content in caryopsis flowering late was more than caryopsis flowering early; grout during the accumulation of starch and protein accumulation rate and caryopsis flowering early below the average accumulation rate decreased from0.07to0.46and0.026-0.050mg-grain-1·d-1, were reduced accumulation of3.0-6.1and0.3-1.1mg-grain-1; starch accumulation especially protein peak time was delayed, delayed respectively to14and7to921d; endosperm starch granule cells is significantly slower than the formation of caryopsis flowering early, arranged in a loose, protein bodies appeared much later in the caryopsis flowering early, volume was significantly smaller. The application of panicle nitrogen fertilizer spikelets significantly reduced starch and protein accumulation rate and accumulation, especially for caryopsis flowering late greater impact, its starch and protein accumulation rate in the high nitrogen levels than non-panicle Shi panicle nitrogen were reduced from0.14to0.17and lowering0.0023-0.0064mg-grain-1·d-1accumulation was reduced by2.7to4.9and lower0.17-0.23mg·grain-1; affect late flowering Ying flowers endosperm starch granules and protein in the formation, so that the formation of starch granules slower, smaller, more loosely arranged, protein bodies appeared much later time, smaller. Different varieties have different response on panicle nitrogen, effects on starch accumulation of Wuyunjing23were greater than Wuyujing3, and effects on protein accumulation of Wuyujing3were greater than Wuyunjing23.3. Clearing effects of panicle nitrogen fertilizer on endogenous hormones in caryopsis different flowering sequence. Early grain filling stage caryopsis flowering early in grains IAA, GAs, Z+ZR and ABA were higher than in caryopsis flowering late; into bloom at different times in the late grouting spikelets grain IAA, GAs and Z+ZR content in smaller differences and ABA content in quite different, caryopsis flowering early was significantly lower than caryopsis flowering late, reduced by about30to60%. Panicle nitrogen fertilizer flowering at different times GAs Grains spikelets and Z+ZR content has little effect, while the ABA, IAA, especially a greater impact. Panicle with and without nitrogen application compared to the high nitrogen significantly improved late flowering panicle grain ABA content, the peak improved by about30to70%; delayed peak value occurs ABA time delay0-15d; widening the early and caryopsis flowering late differences. But Wuyunjing23and Wuyujing3did not behave consistently, and did not appear regularity.4. Part of the mechanism that panicle nitrogen fertilizer affected rice grain filling was clarified. Panicle nitrogen fertilizer of application widened early and caryopsis flowering late between accumulation of dry matter and carbon and nitrogen compounds, ABA content, endosperm starch granules and protein formation differences postponed caryopsis flowering late starch and proteins grouting material accumulation start time and the peak of the caryopsis flowering late reduced during grain filling rate and improve the caryopsis flowering late grain ABA content, slowed endosperm starch granules and protein body formation rate, the endosperm cells starch granules and protein bodies smaller size, starch granules loosely arranged proteomic changes occur later time, thereby affecting the spikelets grout.