Effects Of Two Different Selenium Fertilizers On Grain Selenium Accumulation And Quality-related Traits Of Rice

Selenium(Se)is a kind of multi-functional and necessary life element for human body,which can only rely on food intake.Nutrition and health organizations at home and abroad believe that appropriate increase of Se intake is helpful to enhance human immunity.Most of China’s agricultural production areas are located in natural Se deficient regions,and most people’s daily Se intake is lower than the national recommended standard.Rice(Oryza sativa.L)is the most important food crop in China.Therefore,the research and development of Se-enriched rice is an effective way to improve people’s Se-intake.It is reported that the application of Se fertilizer in Se deficient regions can significantly increase the Se content in rice,but also increase the cost.In addition,there are few studies on the effects of different Se fertilizers on Se accumulation and Se forms in grains of different rice varieties,which affects the trust degree of choosing Se-enriched rice to increase Se intake to a certain extent.In this study,three different concentrations of two commercial Se fertilizers(liquid Se fertilizer and granular Se fertilizer)were applied to four different rice varieties.After rice ripening,the changes of grain Se contents,Se forms,heavy metal contents,beneficial microelements contents and quality-related traits under different treatments were comprehensively determined.The results will provide a theoretical reference for how to develop Se-enriched rice more economically and effectively in rice production,and for consumers to choose Se-enriched rice to improve the level of Se intake,which has important practical significance.The main results are as follows:1.We found different Se fertilizers,application concentrations and varieties had significant interaction effects on Se accumulation in grains,indicating that the purpose of saving cost and increasing efficiency could be achieved by selecting Se fertilizers,varieties and application concentrations reasonably in the production of Se-enriched rice.Compared with the control,the Se contents of brown rice and milled rice could be significantly increased by applying two kinds of Se fertilizers at three concentrations,and there was a significant positive correlation between Se content and application concentration.There were significant differences in Se enrichment ability among different varieties.The grain Se content of each variety under the treatment of granular Se fertilizer was slightly higher than that of liquid Se fertilizer,but the transfer efficiency of Se under the treatment of liquid Se fertilizer was significantly higher than that of granular Se fertilizer.2.The contents of organic Se in all varieties were more than 97%except for the variety Sul 785(95.5%)under the high concentration of Se fertilizer,indicating that most of Se in Se-enriched rice obtained by Se application in vitro could be absorbed by human body.The content of organic Se in rice grain under the treatment of granular Se fertilizer was slightly higher than that of liquid Se fertilizer.Selenomethionine(SeMet)is the main component of organic Se,followed by selenocysteine(SeMeCys)and selenomethylselenocysteine(SeMeCys).The proportion of SeMet under the treatment of liquid Se fertilizer was lower than that of granular Se fertilizer,but the proportion of SeMeCys under the treatment of liquid Se fertilizer was significantly higher than that of granular Se fertilizer.3.The contents of As,Pb and Cd in rice grains were significantly reduced by application of two different Se fertilizers,and the effects were more obvious with the increase of Se concentration.For liquid Se fertilizer,the contents of As in rice grains between the treatments of control and low concentration of Se(group 1),and of low and medium Se concentration(group2),and of medium and high Se concentration(group 3),were decreased by 19.25%,29.5%and 56%,respectively.Similarly,the contents of Pb in groups 1,2 and 3,were decreased by 21.75%,33.75%and 43.75%,respectively;the contents of Cd were decreased by 55.55%,79%and 90.25%,respectively.For granular Se fertilizer,the decreased contents of As were by 16.55%,29%and 41.75%,by 27%,39.25%and 62.5%for Pb,and by 60.25%,78.5%and 85.5%for Cd,in groups 1,2 and 3,respectively.Together,these results suggested that applying Se fertilizer could inhibit the accumulation of the three heavy metals in rice grains.