中文摘要：

【目的】施用氮肥是农业生产上最重要的增产措施之一,但增施氮肥对不同生育期小麦植株中硒累积、转运和分配的影响尚不明确。本研究通过盆栽试验研究不同氮水平对小麦生长过程中植株各器官硒累积的影响,为合理施氮提高小麦硒含量提供理论参考。【方法】试验设置N 100 mg/kg和200 mg/kg两个水平,每个氮水平设置低硒（Se 0.81 mg/kg）和高硒（Se 5.02 mg/kg）处理,分别在小麦苗期、拔节期、孕穗期、抽穗期、扬花期、灌浆期和成熟期取样,分析不同生育期小麦对土壤外源硒的吸收速率,探讨不同硒水平下施氮量对小麦各器官硒累积、转运和分配的影响。【结果】1）与低氮相比,高氮促进了小麦籽粒产量增加,低硒的促进作用大于高硒,低硒和高硒时的高氮处理小麦籽粒产量较低氮处理分别提高了21.7%和13.7%。低硒时的高氮处理能提高小麦穗（特别是籽粒）和老叶中的硒含量,籽粒和颖壳硒含量较低氮处理分别提高了31.2%和13.6%,但高硒时高氮处理却导致小麦各器官（特别是籽粒和根）中硒含量下降,其中籽粒和根部硒含量较低氮处理分别下降了13.2%和17.8%。2）相同硒水平下,高氮处理小麦根部硒占植株总硒的比例较低氮处理下降了约1/4;在营养生长阶段,低硒时高氮处理能促进硒向小麦地上部转运,而在生殖生长阶段其能促进硒从小麦茎叶向颖壳和籽粒中转运,使得籽粒中硒占总硒比例提高了18.4%;但高硒时高氮处理却促进硒从茎叶转运到颖壳中,致使籽粒中硒占总硒比例下降了8.0%。3）小麦根部硒含量在苗期和拔节期,抽穗期和扬花期之间增长幅度最大,说明此期间是小麦硒吸收的敏感期。【结论】小麦硒含量因生育期和外源硒水平的不同而异,施氮量也影响着小麦硒累积、转运和分配。增施氮肥能提高硒的利用效率,建议低硒地区农业生产中补硒时要结合?

英文摘要：

【Objectives】Nitrogen application is one of the most important measures for increasing crop yield in agriculture,but impact of nitrogen application on accumulation,translocation and distribution of selenium in winter wheat at different periods is not clear. 【Methods】A pot experiment was carried out to study effect of nitrogen application on selenium accumulation of winter wheat at different growth periods for providing theoretical reference of reasonable nitrogen application and increasing selenium content of grains. Wheat was grown under greenhouse conditions with 100 mg / kg or 200 mg / kg nitrogen,and each nitrogen treatment was supplied with low（ Se 0. 81 mg / kg） or high（ 5. 02 mg / kg） levels of selenite. Selenium concentrations and biomass amounts of different parts of wheat were determined at 7 stages of seedling,jointing,booting,heading,flowering,filling and maturity. The selenium contents of wheat in different treatments and the selenium absorption amount of roots at different growth periods were analyzed,and the influence of the nitrogen application on selenium accumulation,translocation anddistribution in wheat with the same selenium level was investigated.【Results】The wheat yields under the low and high Se treatments are increased by 21. 7% and 13. 7% with the high N supply,respectively. The Se contents in the grains and glumes under the high N and low Se supplies are 31. 2% and 13. 6% higher than under the low N and low Se treatment,and those in high N and high Se condition are 13. 2% and 17. 8% lower than the low N and high Se condition,respectively. Under the same Se level,the proportion of Se in roots under the high N is about a quarter lower than the low N. The high N and low Se condition promotes the up-transfer of Se during the vegetative growth stage and to the grains and glumes during the reproductive growth stage,and eventually increases the distribution ratio of Se in grains by 18. 4% in total Se. The high N and high Se treatment mainly promotes the transportation to glu