| It has great significance in improving rice quality to study the differences of the quality and starch structure of rice with different amylose content (AC), the development of starch structure, differences among compositions and quality of rice. This study elucidated the relationships between AC and rice quality, mechanism of the development of starch structure. Effects of nitrogen panicle fertilizer application (NPFA) on rice quality and starch structure were also investigated. The main results were as follows:1. In order to research the relationship between AC and rice quality, Wuyunjing7, w3668, Kyou818 and yangfunuo were used in this study. The results showed that pasting temperature (PaT), peak paste viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV) and breakdown viscosity (BDV) decreased with AC of rice increased, while setback viscosity (SBV) increased. But among the four rice cultivars, the higher ACof rice not showed the lower PKV and BDV; There was significant negative correlation in AC and relative crystallinity of rice; There weren't distinct differences among starch structure with different AC of rice, but differences existed between rice cultivars with AC <10% and >10%, large numbers of pores existed in the endosperm of low AC and glutinous and in which the arrangement of amyloplast became tighter from abdomen to dorsum. The arrangement of amyloplast showed that glutinous was the best, japonica was the second and indica was the last; The RVA profiles increased after the lipid of rice were removed, which mainly represented that the PKV, BDV,HPV, absolute value of SBV and CPV increased and PT decreased, but degree of influence on the amylograph characters of rice with fat removed were different.2. Effect of NPFA on rice quality and starch structure. The results showed that influences of NPFA on protein fractions were different among rice cultivars. The more NPFA, the higher Glutelin and prolamine content ,but influences of NPFA on albumin and globulin weren't evident; and with the NPFA increased , the AC decreased, the protein content enhanced and the length of Gel .consistency fell. Influence of NPFA on the ratio of AP/AC was different among rice cultivars. Effects of NPFA on rice RVA profiles presented total curves decreased with increasing NPFA, namely increasing rates of nitrogen ertilizer reduced PKV, HPV and CPV. However, RVA profiles of hybrid indica and glutinous rice cultivars didn't show clearly decline trends than that of japonica cultivars. The results also showed that the relative crystallity fell with increasing rates of NPFA, which behaved that the two separate peaks at 17°and 18°gradually translated into one peak, especially the height of peaks at 18°increased. Numbers of protein body increased and the size of amyloplast became unanimous with increasing NPFA. Too high and too low NPFA loosened amyloplast arrangement and widened the gap between amyloplasts.3. Mechanism of the development of rice grain and starch structure formation. The results showed that AC increased and dry weight of grain gradually improved with "s" type from 5d after anthesis during grain filling stage, and the size of amyloplast grow bigger and the shape varied from elliptical to polygon. With the development of grain, the amyloplasts were pressed into polyhedron and the X-ray diffraction intensity of starch strengthened, and the diffraction pattern gradually approach to A type and relative crystallinity of starch intensified.4. Effect of NPFA on the composition and quality in different position of rice. Results showed that protein and free amino acid content especially in the outset part of rice were significant enhanced with increasing NPFA, and all protein fractions increased to different extent. But AC, relative crystallinity, PKV, HPV, CPV and SBV of different part in grain fell with increasing NPFA, and BDV enhanced. The results implied that rice quality and arts and crafts quality could be improved by proper NPFA.
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