【摘要】 为探明施氮量对花后弱光胁迫下软质小麦氮素吸收与转运特性、氮肥利用效率及产量品质形成的影响机制，在盆栽条件下，以软质小麦品种荃麦725（QM725）为材料，采用¹⁵N示踪法，试验共设置2个氮素水平，即N1（N 120 kg/hm²）、N2（N 180 kg/hm²）,每个施氮水平下于小麦灌浆期（开花后7～35 d）设置2个遮光处理，即CK（不遮光）,SH（遮光30%）。分析施氮量与花后弱光条件下软质小麦籽粒产量和品质之间的形成关系，研究不同氮肥用量对花后弱光条件下软质小麦氮素积累、转运及籽粒产量与品质的影响。结果表明，与对照相比，N1和N2条件下，花后弱光处理显著降低了开花期植株以及成熟期营养器官氮素积累量，且来源于肥料氮的比例显著高于土壤氮，而成熟期籽粒氮素积累量来源于土壤氮的比例显著高于肥料氮，其肥料氮在相同施氮量条件下，基施氮肥比例大于追施氮肥。在相同弱光处理条件下，N2较N1相比，提高了开花期肥料氮积累量、成熟期总氮与肥料氮积累量和成熟期籽粒总氮、肥料氮与土壤氮积累量。在N1和N2处理水平条件下，随着花后光照强度的降低，小麦氮素收获指数、氮肥收获指数、氮肥生产效率、穗粒数、千粒质量和籽粒产量均显著下降。软质小麦籽粒蛋白质、淀粉含量及其积累量随着氮肥用量的增加显著提高。但在相同施氮量条件下，弱光胁迫降低了籽粒淀粉含量、蛋白质和淀粉积累量。花后弱光胁迫显著影响了软质小麦植株氮素积累，降低了小麦花后营养器官贮藏物质向籽粒的转运效率，导致营养器官对籽粒的贡献率降低，从而不利于植株整体的氮素转运效率。随着施氮量的提高，小麦的氮素收获指数、氮肥收获指数、氮肥生产效率及氮素利用效率均显著提升。在相同施氮量N1和N2处理条件下，花后弱光胁迫显著降低了软质小麦籽粒蛋白质和淀粉积累量，进而影响了粒质量的形成，从而导致产量降低。更多还原

【Abstract】 To explore the effects of nitrogen application rate on nitrogen uptake and translocation characteristics, nitrogen use efficiency, and the formation mechanisms of yield and quality in soft wheat under weak light stress during the after anthesis stage, under pot conditions, the soft wheat variety Quanmai 725（QM725）was used as the material, and the ¹⁵N tracer method was used.Two nitrogen rates were set in the experiment, namely N1（N 120 kg/ha）,N2（N 180 kg/ha）,and two shading treatments were set at the wheat filling stage（7—35 d after anthesis）under each nitrogen application rate, namely CK（no shading）,SH（30% shading）.The relationship between nitrogen application rate and grain yield and quality of soft wheat under weak light after anthesis was analyzed, and the effects of different nitrogen application rates on nitrogen accumulation, transport, grain yield and quality of soft wheat under weak light after anthesis were studied.The results showed that compared with the control, under the conditions of N1 and N2,the nitrogen accumulation of plants at flowering stage and vegetative organs at maturity stage was significantly reduced by weak light treatment after anthesis, and the proportion of nitrogen from fertiliser was significantly higher than that from soil nitrogen, while the proportion of nitrogen accumulation in grains at maturity stage from soil nitrogen was significantly higher than that from fertiliser nitrogen.Under the same nitrogen application rate, the proportion of basal nitrogen fertiliser was greater than that of topdressing nitrogen fertiliser.Under the same weak light treatment conditions, compared with N1,N2 increased the accumulation of fertiliser nitrogen at flowering stage, the accumulation of total nitrogen and fertiliser nitrogen at maturity stage, and the accumulation of total nitrogen, fertiliser nitrogen and soil nitrogen at maturity stage.Under N1 and N2 treatments, the nitrogen harvest index, nitrogen harvest index, nitrogen production efficiency, grain number per spike, 1000-grain weight and grain yield of wheat decreased significantly with the decrease of light intensity after anthesis.The content and accumulation of protein and starch in soft wheat grains increased significantly with the increase of nitrogen fertilizer.However, under the same nitrogen application rate, weak light stress reduced the starch content, protein and starch accumulation in grains.Weak light stress after anthesis significantly affected the nitrogen accumulation of soft wheat plants, reduced the transport efficiency of storage substances from vegetative organs to grains after anthesis, resulting in a decrease in the contribution rate of vegetative organs to grains, which was not conducive to the overall nitrogen transport efficiency of plants.With the increase of nitrogen application rate, the nitrogen harvest index, nitrogen harvest index, nitrogen production efficiency and nitrogen use efficiency of wheat were significantly improved.Under the same nitrogen application rate of N1 and N2,after anthesis weak light stress significantly reduced the accumulation of protein and starch in soft wheat grains, which in turn affected the formation of grain weight, resulting in a decrease in yield.更多还原