中文摘要：

采用SDS-PAGE电泳和切胶比色进行亚基定量的方法，研究施氮量对2个小麦品种籽粒HMW-GS和GMP积累的影响。结果表明，高蛋白小麦品种徐州26在花后14dHMW—GS就开始形成，低蛋白品种宁麦9号在花后21d才开始形成。增施氮肥对小麦灌浆前期HMW—GS的形成作用不明显，而有利于徐州26HMW—GS积累速度的提高和HMW—GS快速积累期的延长，及宁麦9号灌浆后期HMW—GS的积累，导致成熟期徐州26HMW—GS和GMP含量随施氮量增加而提高；但施氮过多则降低宁麦9号籽粒HMW—GS和GMP含量。相同氮素水平下，籽粒HMW—GS各亚基含量徐州26均高于宁麦9号，表明籽粒HMW—GS亚基含量与小麦品质性状密切相关。

英文摘要：

Accumulations of high molecular weight glutenin subunits （HMW-GS） and glutenin macropolymer （GMP） play key roles in grain quality of wheat （ Triticum aestivum L. ）. The aims of this study were to analysis dynamic changes in contents of each high molecular weight glutenin subunit and GMP, and evaluate effects of nitrogen rates on contents of HMW-GS and GMP in grains of two wheat cuhivars, Xuzhou 26 and Ningmai 9, which contained similar type of HMW-GS while differed in protein content in grain. HMW-GS were firstly separated using the sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE）, and each of the HMW-GS in the gel was cut and extracted, then measured quantitatively by colorimetric analysis. Five nitrogen rates of 0, 75, 150, 225 and 300 kg· ha^- 1 were established for each cultivar. The results showed that all HMW-GS in high grain protein content cuhivar Xuzhou 26 were formed in grain at 14 days after anthesis （DAA）, while those of low grain protein content cuhivar Ningmai 9 at 21 DAA. Nitrogen application showed no impact on the early formation of HMW-GS in grain of both cuhivars. Grain HMW-GS accumulation rate was increased and the rapid accumulation period prolonged with the increasing nitrogen rate in Xuzhou 26, while HMW-GS accumulation rate during late grain filling period was enhanced in Ningmai 9. Thereafter, the contents of total HMW-GS and GMP increased with the nitrogen rate in grain of Xuzhou 26. In Ningmai 9, however, the contents of total HMW-GS and GMP increased within the nitrogen rates from 0 to 225 kg·ha^- 1 , while decreased when excessive nitrogen of 300 kg· ha^- 1 was applied. Under the same nitrogen rate, each content of HMW-GS in grain of Xuzhou 26 was higher than that of Ningmai 9, indicating the key role of HMW-GS in wheat quality. In conclusion, the higher HMW-GS content is related to the earlier starting time of HMW-GS synthesis, and moderate nitrogen application favors synthesis of HMW-GS in wheat grain.