烯效唑干拌种对小麦氮素积累和运转及籽粒蛋白质品质的影响

通过田间试验,研究了不同烯效唑干拌种剂量对3个不同筋力小麦品种植株氮素积累、运转和籽粒蛋白质品质的影响,结果表明,基因型、环境及烯效唑处理对小麦品质的影响效应依次减小,且均达到了极显著水平,但三者的互作效应较小。烯效唑处理后提高了不同生态点下不同小麦品种籽粒蛋白质含量和产量,处理后的面筋含量和沉淀值增加,面团形成时间和稳定时间延长;干拌种增加了开花期各营养器官中的氮素含量和单株氮素积累量,花后氮素总转移量、总转移率及其对籽粒氮的贡献率极显著提高,且处理后旗叶中可溶性蛋白质含量在花后15 d内均显著高于对照;对籽粒中氮含量而言,烯效唑处理后提高了灌浆初期籽粒中的非蛋白氮含量,花后5—20 d内均高于对照,灌浆期间籽粒蛋白氮含量均高于对照,因而处理后的粗蛋白质含量变化动态特点为谷底高、回升快。研究认为,烯效唑处理如同基因、环境一样独立影响小麦籽粒品质,而烯效唑处理后提高了开花初期旗叶中的可溶性蛋白质含量和花前营养器官中氮素含量及花后氮素转运量,可能是其提高籽粒非蛋白氮含量、促进籽粒蛋白质含量增加和蛋白质质量提高的重要原因之一,烯效唑干拌种对小麦籽粒蛋白质品质的改善具有广适性。

Effects of uniconazole dry seed dressing on nitrogen accumulation and translocation and kernel protein quality in wheat

Wheat is the main food crop grown and consumed in Sichuan province, but the poor quality and inadaptability of the food processing industry has become a bottleneck for development of the Sichuan wheat industry. Uniconazole belongs to a group of triazoles, which were developed as a high efficiency, low toxic and residual plant growth retardant, Uniconazole plant growth regulators have a strong influence on seedling cultivation and markedly increase yields. Dry seed dressing is a safe and environmentally friendly method of chemical application compared with foliar application. However, its effect on wheat protein quality is rarely reported, so the relevant theoretical basis for increased wheat protein quality in response to uniconazole treatment is unclear. Therefore, the objectives of this study were, firstly, to study the effects on protein content, gluten content and quality, and dough rheological properties of different uniconazole concentrations (0, 20, 40, and 60 mg/kg) in three different gluten wheat cultivars (medium-weak gluten wheat Chuanmai 32 and Chuanmai 107, and medium-strong gluten wheat Chuanmai 36) in four representative wheat-growing regions in Sichuan (Qionglai in the West Sichuan Plain wheat area, Jingyan in the central Sichuan shallow-hills wheat area, Hanyuan in the southwest Sichuan mountains wheat area, and Yaan in the montane wheat area around the Sichuan Basin). Secondly, we studied the effects of uniconazole dry seed dressing on nitrogen accumulation in vegetative organs and its transportation to grains, dynamics of the soluble protein content of the flag leaf, and dynamics of grain protein and non-protein nitrogen content. Thirdly, we explored the effect and mechanism of uniconazole dry seed dressing on nitrogen accumulation and translocation as well as the protein quality of the wheat kernel. The results showed that genotype, environment and uniconazole highly influenced wheat grain quality, and their effects decreased significantly in turn, but the interaction effects were much weaker. Under different ecological conditions, the kernel protein content and yield, wet gluten content, sedimentation value, and dough development and stability time were improved significantly by uniconazole treatment. Uniconazole dry seed dressing increased the nitrogen content in vegetative organs and improved nitrogen accumulation per plant at the flowering stage; the total nitrogen translocation amount and rate after anthesis, together with its contribution to kernel nitrogen content, was enhanced significantly. Uniconazole treatment increased the soluble protein content in the flag leaf during the 15-day period after anthesis. Regarding the protein content in kernels, the non-protein nitrogen contents at the onset of anthesis and in the period 5-20 days after anthesis, as well as protein nitrogen content during grain filling, were higher with uniconazole treatment than in the control. Accordingly, the crude protein content was high at the bottom and climbing back rapidly. In summary, uniconazole treatment affected wheat kernel quality independently of genotype and environment. Uniconazole dry seed dressing increased the soluble protein content in the flag leaf at the early flowering stage, promoted nitrogen accumulation in vegetative organs before anthesis, improved nitrogen translocation from vegetative organs to kernels after anthesis, and enhanced the non-protein nitrogen content of kernels, all of which may be major reasons for the promotive effect of uniconazole on grain protein content and quality. The latter effects of uniconazole are of broad applicability.