Study On Non-Structural Carbohydrates Translocation Characteristic And Yield And Quality Formation In Rice

The grain filling substance mainly comes from stem-sheath storage mater and photosynthate after heading, the former count for one third. Stem-sheath stored Non-Structural Carbohydrates (NSC) is not only a part of filling substance, but also effect grouting starting and grain-filling. It mainly influences the cell division and development of endosperm.With medium and large panicle varieties as experimental materials, On the basis of their translocation characteristics of NSC in the stem and sheath, we researched the effects of panicle nitrogen fertilizer and spikelets-removing on the translocation of NSC and yield-quality formaton emphatically for variety improvement and perfection of cultivation technique. The main results were as follow:1. The translocation of NSC in stem and sheath was very different between large and medium panicle rice variety. The large panicle rice cultivar had the potentiality of super high yield because of its powerful production capacity of Photosynthetic matter. The translocation of NSC from stem-sheath mainly concentrated in 10～15days after heading, during this period, NSC translocated from stem-sheath of large panicle variety were less than those of medium panicle variety. During late Grain filling Period, NSC reaccumulated in stem-sheath of large panicle seriously. The reason why the seed setting rate and 1000-grains weight of large paicle variety was lower was the less occupancy of stem-sheath stored NSC for every floret. Therefore, how to use the reasonable measures to regulate the large panicle variety and make every floret start filling soon and successfully was the key to further increase grain yield.2. We researched the effect of panicle nitrogen fertilizer amount on translocation of NSC and yield and quality formation. The results indicated that, Compared to control, the application of panicle nitrogen fertilizer decreased NSC accumulated in the stem-sheath in the full heading stage and mature, it also decreased the translocation of stem-sheath stored NSC during 15 days after full heading or from full heading to mature. Adequate application of panicle fertilizer could increase yield obviously. Application of panicle fertilizer could increase the head rice rate, but had little effect on the brown and milled rice rate, increasing the application of panicle fertilizer, appearance quality improved, but cooking and eating quality would get worse. NSC stored in stem-sheath effected yield formaton, analysis indicated that, NSC of stem-sheath occupied or obtained for one Spikelet was significantly correlated with seed setting rate.3. By spikelet-removing treatment, we research the effects of sink change on the stem-sheath stored NSC translocation and quality of hybrid rice. The results were as follows: Through the treatment of spikelet-removing, peak content of NSC in stem and sheath appeared later. During the 15 days after heading or from heading to mature, translocation amount of stem-sheath stored NSC decreased significantly and in the mature, NSC reaccumulated seriously in the stem-sheath. Compared to control, filling speed of the inferior grains accelerated significantly and the date of their weight increase appeared earlier. External quality improved obviously by Spikelet-removing, but there was no effect on milling quality, its effect on cooking and eating quality varied with varieties.