Study On The Interaction Of Phosphorus And Selenium In Winter Wheat

As one of the most essential microelement for human body and animals,selenium(Se)has the effect of cancer prevention,anticancer and immunologic enhancement.However,in China,72 percent area and about 7 hundred million people lack Se in their bodies and can affect health and life seriously.Winter wheat is the main food for people in Northern China as the most important food crop in our country.It is very important for human supplementing Se nutrition to regulate and control the content of Se in winter wheat grain.In this text,we studied the effect of the combining of phosphorus(P)and Se fertilization on the photosynthetic characters,yield,components and combined forms in grain of winter wheat by pot experiment and investigated the plausible mechanisms of P and Se interaction effect of winter wheat preliminarily via the absorption and transport of P and Se and soil Se transformation.The results show that:1.There exists significant interaction effect between P and Se under the condition of pot culture.2.Se addition inhibit the photosynthesis of winter wheat in each stage under the condition of P deficiency(P0).Enriching a certain amount of Se fertilizer(Se0.5)can improve wheat photosynthesis and suppress aging of wheat in the filling stage but the excess amount of Se(Se1)decrease the photosynthesis with the addition of P(P80,P160).The application of P inhibits the photosynthesis of winter wheat in booting stage and increases the photosynthesis in blooming and filling stages under the condition of Se0 and Se0.5 and also has the effect of delaying senescence.3.Combining application of a certain amount of Se fertilizer under the condition of normal P level(P80)can increase the yield and yield components of winter wheat and the maximums of yield and grains per ear are both in the P80Se0.5 treatment.4.The application of Se can increase the content and cumulant of Se in every position of winter wheat significantly.In addition,there is antagonistic effect between P and Se in the aspect of plant Se absorption.In the condition of Se application,the addition of P inhibits the absorption and transformation of Se in plants significantly leading to the decrease of Se content of every organ in winter wheat and the inhibition effect is stronger obviously in the condition of the P application than that in the condition of P deficiency.The application of P inhibits the transformation of Se from underground parts to overground parts and from glumes to grains and decrease the Se allocation proportion in grains and stem leaf.The application of P can increase the content and cumulant of P in every position of winter wheat significantly.Under the condition of P(P80,P160),the application of appropriate Se can improve the P content and cumulant in underground part,stem leaf and glume but inhibit the transformation of P from glumes to grains leading to the grain content and cumulant of P and allocation proportion.5.The content of OM-Se can be increased significantly by exogenous Se fertilizer addition and specific performance in the significant increase Se content of protein,polysaccharide and nucleic acid bound forms.Applicating P fertilizer and exogenous Se fertilizer simultaneously decreases the OM-Se content in wheat grains but increases the proportion of OM-Se to total Se.6.The application of P decreases both Cu and Zn contents but increases Mn content.Se addition decreases Mn content in wheat grains and the appropriate Se(Se0.5)content increases the Cu,B,Zn and S contents and under the condition of normal P application,the addition of Se can increase the Fe content in grains.7.The application of Se can increase each form of Se content in soil and increase the proportion of their available contents to total contents.Under the condition of Se(Se0)deficiency,the application of P can increase the proportion of water-soluble Se,exchangeable Se and Fe-Mn oxides bound Se to total Se in soil and bringing about the increase of soil available Se content.Under the condition of Se(Se1),the application of P increases the proportion of soil water-soluble Se,organic matter-sulfide bounded form Se and residual Se contents to total Se content,but decrease the ratio of exchangeable Se,Fe-Mn oxides bound Se contents.The application of P decreases the ratio of soil available Se content.