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[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。
[Objective] The research aimed to reveal the mechanism of nitrogen utilization in wheat during different times of nitrogen application. [Method] The effects of topdressing nitrogen fertilizer on nitrogen uptake, distribution, transportation and yield of high quality wheat were studied by isotope tracing technique. [Result] The results showed that under the experimental conditions, the nitrogen uptake by wheat accounted for 73.36% -78.58% from the soil and from 21.42% to 26.64% from the fertilizer. Topdressing and flagging during the topdressing nitrogen fertilizer can promote plant nitrogen uptake, especially on the absorption of fertilizer nitrogen, to improve nitrogen flowering stage organs and maturity of the grain allocation and distribution of the proportion of organs to promote vegetative organs after flowering Nitrogen transfers to grain. 74.08% ~ 80.28% of the nitrogen content of wheat grain is the transport of nitrogen in vegetative organs before flowering. The contribution of vegetative organs to the grain is leaf> stem> cornicle> glume shell> leaf sheath> root. Appropriate nitrogen recovery increased grains per spike and increased harvest index and yield. [Conclusion] Nitrogen recovery at different periods had obvious regulation on the nitrogen metabolism, yield and quality of wheat.