水稻种子蛋白质的组成和积累形态对稻米品质的影响

设置水培试验对‘16-17’（谷蛋白前体聚合物明显,含量高）和‘16-20’（谷蛋白前体聚合物不明显,含量低）分别进行CK（氮2800 μmol/L,硫80 μmol/L）、N（氮3640 μmol/L,硫80 μmol/L）、S（氮2800 μmol/L,硫260 μmol/L）、N+S（氮3640 μmol/L,硫260 μmol/L）处理,以此改变稻米品质和稻米贮藏蛋白质的组成与含量,从而对稻米蛋白质各组分及相关品质性状进行分析。结果表明：（1）在N、S和N+S的不同处理下均增加了粗蛋白的含量,使‘16-20’的稻米粗蛋白百分含量分别增加2.35%、2.67%和2.73%;（2）在2个品种的各组分蛋白含量变化中,‘16-17’的醇溶蛋白和谷蛋白的百分含量在N、S和N+S下较对照分别增加了9.75%、4.21%和4.67%,3.92%、7.38%和12.92%。‘16-20’的谷蛋白百分含量在S和N+S处理下增加了17.72%和29.38%,醇溶蛋白百分含量在N+S下增加了3.73%,而球蛋白百分含量在N、S和N+S三个处理下降低了2.86%、3.78%和3.69%,清蛋白在N、S处理下显著降低;（3）谷蛋白的2个亚基的相对含量和57 kDa谷蛋白前体及57 kDa以上谷蛋白聚合体的积累在‘16-20’品种中明显增加。（4）稻米品质中,N、S配施对2个参试品种的碾磨品质性状的影响不明显,但有利于2个品种稻米外观品质和食味品质的改善,并使‘16-20’的营养品质显著增加,另外,‘16-20’的千粒重在S和N+S处理下显著增加。故不同N、S配施处理下,不同品种水稻贮藏蛋白质的组成和积累形态差异很大,并改变了含巯基蛋白质组分的积累量和积累形态。尤其是在富S条件下,蛋白质积累过程中形成较多的巯基及二硫键,并通过二硫键来改变含巯基的蛋白质亚基之间的聚合程度,形成不同分子量的谷蛋白聚合体,使蛋白质的积累形态发生明显改变,进而使稻米相关品质性状发生改变。

Effects of Rice Seed Protein Composition and Accumulation Morphology on Rice Quality

A hydroponic test is set for the processing of CK (nitrogen 2800 μmol/L, sulfur 80 μmol/L), N (nitrogen 3640 μmol/L, sulfur 80 μmol/L), S (nitrogen 2800 μmol/L, sulfur 260 μmol/L) and N+S (nitrogen 3640 μmol/L, sulfur 260 μmol/L) for the ‘16-17’ (with high content of the precursor polymer of glutelin) and ‘16-20’ (with low content of the precursor polymer of glutelin), by changing the rice quality and the composition and content of rice storage protein, in order to analyze the rice protein components and related quality traits. The crude protein content increased under different processing of N, S and N+S, that of ‘16-20’ significantly increased by 2.35%, 2.67% and 2.73%. The content of prolamin and glutelin of ‘16-17’ increased by 9.75%, 4.21% and 4.67%, 3.92%, 7.38% and 12.92%, respectively for the two varieties. The glutelin content of ‘16-20’ significantly increased by 17.72% and 29.38% under the processing of S, the prolamin content increased by 3.73% under the processing of N+S,the percentage of globulin was reduced by 2.86%, 3.78% and 3.69% under the processing of N, S and N+S., and the albumin significantly reduced under the processing of N and S. The relative content of the two subunits of glutelin, 57 kDa glutelin precursor and glutelin polymer obviously increased in ‘16-20’. With regard to rice quality, the combined application of N and S didn’t generate obvious impact on the grinding quality of the two varieties, but was conductive to improving the appearance quality and taste quality of the two varieties, and significantly increased the nutritional quality of ‘16-20’. Besides, the thousand seed weight of ‘16-20’ significantly increased under the processing of S and N+S. Hence, under the combined application of N and S, the protein stored in different varieties of rice has great difference in the component and accumulation form, and changes the accumulation amount and accumulation form of the compounds containing sulfydryl proteins. Especially in the condition of abundant S, the protein forms much sulfydryl and disulfide bond in the accumulation process and changes the polymerization contents among protein subunit containing the sulfydryl through disulfide bond to form glutelin polymer with different molecular weight. As a result, the accumulation form of the protein has obvious change, further changing the relevant quality of rice.