Differences in characteristics of quality and related enzymes activity of different wheat cultivars

Chinese. 根据小麦成熟期籽粒的蛋白质、谷蛋白大聚合体(GMP)、湿面筋含量及沉降值、面团稳定时间等蛋白质品质指标的差异，用聚类分析的方法将供试的9个小麦品种分为3组：高GMP含量、高面团稳定时间组；低GMP含量、低面团稳定时间组；中GMP含量、中面团稳定时间组。研究在籽粒灌浆过程中，可溶性蛋白含量、蛋白质合成与分解过程相关酶活性的变化动态，及与蛋白质品质指标的关系。结果表明，蛋白质含量与GMP含量、沉降值、面团稳定时间之间无显著相关性，GMP含量与诸品质指标呈显著正相关，表明GMP含量更能代表加工品质的优劣；灌浆前中期硝酸还原酶（NR）、谷氨酰胺合成酶（GS）活性对可溶性蛋白（SB）含量有显著影响，灌浆中后期内肽酶（EP）、羧肽酶（CP）、氨肽酶（AP）活性对可溶性蛋白含量有显著影响；高GMP组旗叶可溶性蛋白含量显著高于中GMP组和低GMP组。以上结果表明，在灌浆过程中，较高的可溶性蛋白质代谢水平，即灌浆前中期具有较高的NR、GS活性和灌浆中后期具有较高的EP、CP、AP活性，是具有较高的GMP含量的生理基础。

English. Nine wheat cultivars with different protein contents, GMP content, wet gluten content, SDS sedimentation, and dough stability time at maturity were classified into three groups: high GMP content and high dough stability time, low GMP content and low dough stability time, and medium GMP content and medium dough stability time. The dynamic changes in the content of soluble protein and the activity of the enzymes in relation to protein synthesis and degradation and their relationships to characteristics of processing quality were studied during grain filling. The results showed that protein content was not related to wet GMP content, SDS sedimentation, and dough stability time but GMP content was significantly related to the said indices, implying that GMP content was more representative to processing quality than protein content. During the early period of grain filling NR and GS activities had significants effect on soluble protein content and during the later period EP, CP and AP activities has significant effects. The group with high GMP content had higher soluble protein content than other groups. The above results indicated that during grain filling, higher soluble protein level, namely high NR and GS activities during the prophase and metaphase, and high EP, CP, and AP activities during the metaphase and anaphase, was the physiological basis for high GMP content.