Effects Of Exogenous Selenium Biological Fortification Method On Rice Selenium Enrichment And Selenium Forms In Grain

Selenium(Se)is one of the essential dietary mineral elements of a human body.Not only the beneficial effects of selenium depend on the content of total selenium,but they also have a close relationship with its chemical existence.Oryza sativa L.is one of the staple foods in our country.Through the application of exogenous selenium,increasing the selenium content in rice is the fundamental way to improve human selenium nutrition from the source.The organic selenium form of selenomethionine in selenium-rich rice means more to the metabolism as well as the nutritional value of selenium in the human body.In order to explore the effects of exogenous selenium biological fortification methods on selenium-enriched rice and rice selenium forms,this article used pot experiment and field experiment to study the supply of exogenous selenium from roots and leaves,as well as the effects of supplying different types of exogenous selenium(Sodium selenium,sodium selenite,selenomethionine,nano selenium,amino acid chelated selenium)at different growth stages of rice(Jointing booting stage,initial panicle stage,poplar pollination stage,filling stage,wax maturity stage)on selenium-enriched rice and rice selenium forms,so that the best exogenous selenium biological fortification method can be screened out to provide reference for the safe use of exogenous selenium on rice.The main results are as follows:1.Compared with the control group,the application of different exogenous selenium at different growth stages has no obvious effect on rice yield,between exogenous selenium treatment,except at the poplar pollination stage,the yield of rice sprayed with nano-selenium was significantly lower than that of amino acid chelated selenium,and at the wax maturity stage,the yield of rice sprayed with nano-selenium was significantly lower than that of sprayed sodium selenium,the differences in rice yield between the other treatments were not significant.2.A pot experiment was conducted to analyze the effects of different application methods of exogenous selenium on rice selenium-enriched and rice selenium forms.The results showed that compared with the control,root application and foliar application of sodium selenite significantly increased the selenium content and organic selenium content in rice.However,the difference in the proportion of organic selenium in rice between the root application and the leaf spray sodium selenite was not significant.,among which selenomethionine accounted for the highest proportion,69.5% and 52.6% respectively.3.The effects of spraying exogenous selenium at different growth stages on the selenium content and morphology of rice were studied using pot and field experiments.The results showed that in the pot experiment,the foliar application of amino acid chelated selenium at the jointing stage of rice resulted in the highest Se Met ratio in rice,which was 66.39%.In the field experiment,the foliar application of amino acid chelated selenium at the jointing booting stage of rice resulted in the highest Se Met ratio in rice,which was 90.72%.It is worth noting that the amino acid chelated selenium sprayed at the jointing stage or jointing booting stage of the pot experiment and field experiment has lower selenium content in rice compared to other growth periods.This shows that spraying selenium during this period can obtain a higher conversion rate of organic selenium in the grains,indicating that the application of exogenous selenium at the jointing or booting stage is the best period for rice to obtain organic selenium.4.Studies on the effects of spraying different exogenous selenium on rice selenium content and selenium form showed that when different kinds of exogenous selenium were sprayed at the jointing booting stage,the selenium content of rice grains was as follows: selenomethionine treatment> sodium selenite treatment> sodium selenium treatment> nano selenium treatment> amino acid chelated selenium treatment;The ratio of Se Met to total selenium in rice is: selenomethionine treatment> sodium selenite treatment>nano selenium treatment>sodium selenium treatment> amino acid chelated selenium treatment.Among them,Se Met accounted for 95.52% of selenomethionine treated rice,Se Met accounted for 85.12% of the rice treated with sodium selenite.It was shown that among the types of exogenous selenium treatments tested,selenomethionine or sodium selenite can obtain better organic selenium enrichment effect in rice.In summary,during the jointing period,foliar spraying of sodium selenite or selenomethionine can get the best selenium-enriching effect from the rice.