The Characteristics Of Selenium Absorption And Accumulation In Rice Plant And The Preliminary Research On Selenium-rich Technical Ways In Rice

1. Application of nano-selenium fertilizer can increase rice plant tillerings, heights and dry matter weights, but there were no significant differences. Nano-selenium fertilizer application had certain stimulation effect on rice yields. Nano-selenium fertilizer can significantly improve the total selenium content and the inorganic and organic selenium content of selenium of rice, which were increased by300%,94%and400%. And the proportion of organic selenium increased from68.6%to85.2%. Application of nano-selenium fertilizer significantly increased the accumulation of Se and As in rice panicle (260%and85%), and inhibitted the Cr, Cd accumulation amount (53%and45%) effectively. There was no significant inhibitory effect on the Pb (0.05%). Nano-Se fertilizer can promote Se transporting to millde rice and bran, and can inhibit to transfer As from the branches to husk and bran. At the same time nano-selenium fertilizer can effectively inhibit accumulation of Cr, Cd, Pb in milled rice.2. The object of this study was to determine the kinetics of accumulation and distribution of Se in rice plant in the soil treated with Se composite fertilizers. The results showed that the Se accumulation in plant tissues positively correlated with the application rate of the Se fertilizer. The related coefficient was more than0.98. Application of nano-selenium fertilizer at seedling stage was an effective agronomic measure to increase rice selenium.A large variation in Se concentration was observed in different plant tissues at different development stages. The highest Se-bioconcentration was observed at the booting stage. And there was a close relationship between leaves and accumulation of selenium in rice panicle. The Se distribution in rice plant at the maturity stage was stem> leaves> rice grain> roots> husk. These results suggest a special flow of Se in rice plant during the growth stage:from roots and stem to leaves at tillering stage, followed by flow from leaves to stem at booting stage, then from roots to leaves and panicle at grain-filling stage, and from leaves to panicle at maturity stage.3. Selenium contents of43conventional japonica rice samples and5japonica hybrid rice samples in Jiangsu Province were determined by hydride generation atomic fluorescence spectrometry, and the effect of nitrogen fertilizer on selenium content in milled rice was also studied. Results showed that the mean selenium contents of conventional japonica rice and japonica hybrid rice were54.7±10.7μg/kg and58.9±8.8μg/kg. An opening up quadratic correlation was found between nitrogen and the selenium concentration in both of conventional japonica rice and japonica hybrid rice. And an opening down quadratic correlation was found between nitrogen and the yields. There was no significant correlation between yields and selenium contents in milled rice. In the high nitrogen fertilizer condition (22.5kg/666.7m2), the selenium contents in conventional japonica rice were101.5-125.0μg/kg, which were higher than the selenium contents in japonica hybrid rice (53.9-70.8μg/kg). Generally, the selenium contents in japonica hybrid rice were higher than conventional japonica rice except in high nitrogen fertilizer condition.