中文摘要：

土壤水分逆境是限制小麦籽粒品质形成的重要生态因子,明确土壤水分逆境下小麦籽粒品质形成的生理机制及调优技术途径,对于深化小麦品质生理生态研究和指导小麦调优栽培具有重要的理论意义和应用前景.在防雨池栽条件下,设置渍水、干旱和对照3个水分处理,每个水分处理下再设置120和240kg·hm^-2两个施氮水平,研究了花后渍水和干旱逆境下氮素对两个籽粒蛋白质含量不同的小麦品种植株氮代谢和籽粒蛋白质积累的影响.结果表明,与正常水分处理相比,花后干旱和渍水均降低旗叶硝酸还原酶活性、叶片总氮含量和游离氨基酸含量.干旱处理提高了茎鞘总氮与游离氨基酸含量以及籽粒蛋白质含量,而渍水处理则使其降低.水分逆境下增施氮肥提高旗叶硝酸还原酶活性、叶片与茎鞘总氮和游离氨基酸含量以及籽粒游离氨基酸和蛋白质含量.花后干旱和渍水均显著降低了小麦籽粒产量和蛋白质产量.增施氮肥提高适宜水分和水分亏缺条件下小麦籽粒产量,但不利于渍水下小麦产量的提高.这说明,花后渍水和干旱逆境下施用氮肥对小麦植株氮代谢和籽粒蛋白质积累有明显的调节效应.

英文摘要：

Soil water stress is the major ecological factor limiting grain quality formation of wheat, while elucidating the physiological mechanism and regulation principles of this formation is of important significance for understanding grain quality physiology and guiding wheat cultural management. In this paper, a cement pool culture experiment was conducted to study the effects of nitrogen supply rate on nitrogen metabolism and grain protein accumulation of two wheat varieties differed in grain protein content under drought and waterlogging. Three water treatments were established from anthesis to maturity, i. e., waterlogging, drought, and moderate water supply （CK）. In each treatment, two nitrogen levels of 120 and 240 kg·hm^-2 were implemented. Compared with CK, both drought and waterlogging significantly reduced the nitrate reductase （NR） activity in flag leaf, and the contents of total nitrogen and free amino acid in leaf, stem and sheath. Drought increased, while waterlogging reduced the contents of total nitrogen and free amino acid in stem and sheath, and that of protein in grain. Under drought and waterlogging, nitrogen supply increased the NR activity in flag leaf, the total nitrogen and free amino acid contents in leaf, stem and sheath, and the free amino acid and protein contents in grain. Both drought and waterlogging stress reduced grain yield and protein yield. Nitrogen supply increased grain yield under CK and drought, but reduced it under waterlogging, illustrating that nitrogen supply could obviously regulate the nitrogen metabolism and grain protein accumulation of wheat from anthesis to maturity under drought or waterlogging.