追氮时期对优质小麦氮素吸收·运转和籽粒产量的影响

目的]揭示小麦不同追氮时期的氮素利用机制。方法]采用同位素示踪技术,研究了不同时期追施氮肥对优质小麦氮素吸收、分布、运转和产量的影响。结果]结果表明:在该试验条件下,小麦吸收的氮素中,来自土壤的占73.36%~78.58%,来自肥料的占21.42%~26.64%。拔节期和挑旗期追施氮肥可促进植株对氮素的吸收,尤其是对肥料氮的吸收,提高氮素开花期穗器官和成熟期籽粒的分配量和分配比例,促使开花后营养器官的氮素向籽粒转移。小麦籽粒氮素的74.08%~80.28%是开花前营养体氮的调运,各营养器官对籽粒的贡献大小为叶片>茎>穗轴+颖壳>叶鞘>根。适期追氮增加了穗粒数,提高了收获指数和产量。结论]不同时期追氮对小麦的氮素代谢、产量和品质具有明显的调节作用。

Influence of Nitrogen Topdressing Stage on Nitrogen Uptake, Translocation and Grain Yield of Wheat with Good Quality

Objective] The study aimed to reveal nitrogen(N) using mechanism of wheat in different N topdressing stage.Method] The influences of dressing N in different stages on N uptake,distribution, translocation and yield of wheat with good quality were studied by isotope tracing technique.Result] Under the experimental condition,73.36%～78.58% of N absorbed by wheat was from soil and 21.42%～26.64% of that was from fertilizer.On the jointing and flagging stage,topdressing N fertilizer could promote the N absorption of plant,especially on fertilizer N and enhance distribution amounts and distribution proportion of N in ear organ during florescence and grain during mature stage,and promote shift of N in vegetative organs to grain after florescence.The 74.08%～80.28% of N in wheat grain was allocated and transported from vegetative N before florescence,and the contribution of vegetative organs to grain: leaf blade > stem > ear axis + glume > leaf sheath > root.Dressing N during suitable time increased grain number per ear,enhanced harvest index and output.Conclusion]Topdressing N fertilizer in different stages had obvious regulation effect on the N metabolism,yield and quality of wheat.