施氮对小麦硒(Ⅵ)吸收、转运和分配的影响

为揭示施氮对小麦硒吸收,转运和分配的影响,通过合理施氮提高小麦硒的利用效率提供理论参考,本研究通过盆栽试验,设置Se1(0.74 mg·kg~(-1))和Se2(2.60 mg·kg~(-1))两个硒酸盐处理;每个硒水平又设为N1(100 mg·kg~(-1))和N2(200mg·kg~(-1))两个氮水平,分别测定了小麦拔节期和成熟期各器官生物量及硒含量.结果表明,升高氮水平使Se1和Se2处理小麦籽粒产量分别提高了13.2%和24.0%.与氮素施用量无关,升高外源硒水平能显著提高小麦各器官中硒含量(P0.01),且以N1处理时效果更显著;Se1处理升高氮水平对小麦硒吸收的促进作用大于Se2处理,Se1和Se2处理升高氮水平使得小麦籽粒硒含量分别提高了22.6%和12.1%.各器官中硒总量占植株硒总量的百分比的大小顺序与富集系数相同,依次为茎叶籽粒颖壳根,升高氮水平促进了小麦根部对硒的吸收和富集,以及营养生长阶段硒向地上部的运移,并使Se1和Se2处理小麦籽粒中的硒总量占植株硒总量的百分比分别提高了11.1%(P0.05)和25.9%(P0.05).因此,施用氮肥可以调控硒的有效性,缺硒地区合理升高氮水平提高了小麦产量及硒含量,而在富硒或硒中毒地区合理施氮肥可缓解硒对小麦的毒害作用.

Effects of Nitrogen Application on Selenium Uptake, Translocation and Distribution in Winter Wheat

In order to better understand the effects of nitrogen application on accumulation, translocation and distribution of selenium in winter wheat and to provide theoretical reference for reasonable nitrogen application and increasing selenium content of grains. A pot experiment was carried out under greenhouse conditions with Se1 (0.74 mg·kg^-1) or Se2 (2.60 mg·kg^-1) levels of selenium, and each Se treatment was supplied with N1 (100 mg·kg^-1) or N2 (200 mg·kg^-1) levels of nitrogen, respectively. Selenium concentrations and biomass amounts of different parts of wheat were determined at jointing and maturity stage. The results showed that grain yield increased with increasing nitrogen levels by 13.2% and 24.0% in Se1 and Se2 treatment, respectively. Regardless of N rate, Se concentration of wheat increased with raising Se amended rate (P<0.01). Increasing nitrogen application could promote Se uptake of root and thus increase the selenium concentration of wheat grains and leaves, which was greater in Se1 treatment than in Se2 treatments. Se concentrations in wheat grain increased by 22.6% and 12.1% with the increasing N application rate in low and high Se treatment, respectively. The distribution ratios of Se in each organ ranked the same as BCFs, following the order of leaf > grain > glume > root. Increasing N fertilization increased the distribution ratio of Se in grains by 11.1% and 25.9% in low and high selenate treatments, respectively. High nitrogen fertilization could promote uptake and translocation of Se in wheat under low Se conditions, and improve Se use efficiency as well in the agricultural production.