氮素水平对小麦籽粒产量和蛋白质含量的影响及其生理基础

Effects of Nitrogen Rates on Grain Yield and Protein Content ofWheat and Its Physiological Basis

在大田高产条件下研究了氮素水平对小麦籽粒产量和蛋白质含量的影响及其生理基础。结果表明 ,适当提高氮素水平既能增加小麦籽粒产量又能提高蛋白质含量 ,使籽粒产量和蛋白质含量达到同步增加 ,氮素水平过高虽能够提高籽粒蛋白质含量 ,但籽粒产量下降。适当提高氮素水平可以提高源器官碳素同化能力和氮素同化能力 ,又能够促进开花前暂贮于营养器官中的同化物质向籽粒中运转 ,增加籽粒中淀粉合成有关酶和氮素同化酶的活性 ,从而导致小麦籽粒产量和蛋白质含量同步增加。氮素水平过高 ,虽能促进源器官和籽粒中的氮素同化能力 ,但由于碳素同化酶和籽粒淀粉合成酶活性降低和开花前暂贮于营养器官中的同化物质向籽粒中的运转效率降低 ,而导致小麦籽粒蛋白质含量提高 ,产量下降。

A field experiment was conducted to study the effects of nitrogen rates on wheat grain yield and protein content and its physiological basis. The results showed that both wheat yield and protein content were improved with reasonable nitrogen rate. Grain protein content was improved, while the yield was decreased with excessive nitrogen. Assimilating capacity of carbon and nitrogen in source organs of wheat was improved, and the redistribution of stored assimilates in vegetative organs before anthesis was improved as well, and activities of enzymes involving in starch synthesis and nitrogen assimilation were also increased when reasonable nitrogen rates were applied. Wheat grain yield and protein content were increased subsequently. Nitrogen assimilation in source organs and grain were improved, while the activities of enzymes involving in carbon assimilation and starch synthesis in grain was decreased, and the redistribution of stored assimilate from vegetative organs to grain was depressed, which led to the protein content increase and yield decrease of grain in wheat.