Effects of nitrogen application on selenium accumulation, translocation and distribution of winter wheat at different growth periods

【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 and distribution 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 glumes, and on the contrary, decreases the ratio by about 8.0% in grain. The absorptions of selenium in roots are high at the seedling and elongation, heading and flowering stages.【Conclusions】 The Se levels in each parts of wheat vary with growth periods and the Se in soil, and the N application influences the accumulation, translocation and distribution of selenium in wheat. High nitrogen fertilization could promote uptake and translocation of Se in wheat under low Se soil conditions, and improve Se use efficiency as well in the agricultural production.