Effects Of Exogenous Selenium On Photosynthetic Characteristics And Selenium Absorption Of Oats During Growth Period

Oat?Avena sativa L.?is a typical gramineous oat herb in annual plants.It has rich nutrients and relatively weak accumulation of selenium.In China,the main oat production area is generally deficient in selenium.The growth of oats is controlled by both genetic factors and the environment.In environmental conditions,fertilization is a factor that has a large effect and is relatively easy to regulate.Proper selenium supplementation to the human body is good for your health.In this study,Baiyan No.2 was used as a material to pass the pot experiment.The root application and foliar application were used to set five exogenous selenium application gradients of 0,9,12,15,and 18 mg·m^-2.The effects of exogenous selenium on the photosynthetic characteristics and selenium absorption of oats during the growth period were studied by measuring,analyzing and comparing the growth index,yield component,photosynthetic parameters and selenium content of each treatment.In order to achieve increased production and income,protect the environment,produce a satisfactory selenium-enriched oats.The results of research on the growth characteristics of oats showed that the application of appropriate concentration of exogenous selenium could promote the growth of oats.When the amount of selenium exceeded 15 mg·m^-2,the growth of oats would be inhibited.This phenomenon can be reflected in plant height,leaf area,stem diameter,root number,total root length,root thickness and root volume.The results of research on the components of oat yield indicate that the appropriate concentration of exogenous selenium can increase the yield component of oats.When the concentration exceeds a certain amount,it has a certain inhibitory effect on the yield components.Exogenous selenium application had significant effects on spikelet number,kernel weight and thousand weight,however,the effect on ear length and kernel number was not significant.The amount of selenium applied in the two treatment methods is the main influencing factor of yield composition.The yield reached its maximum when the concentration was 15 mg·m^-2.The study on photosynthetic characteristics showed that the SPAD value of oat leaves increased first and then decreased with the increase of exogenous selenium concentration in a certain range of exogenous selenium concentration.The net photosynthetic rate?Pn?and stomatal conductance?Cond?increased first and then decreased with the increase of exogenous selenium concentration.Under different selenium concentrations,Pmax,Ic,Is and Rd were observed.There was a significant difference,and the Pmax under root base application 12 mg·m^-22 treatment was the largest,which was 47.7%higher than that of CK.The content of soluble sugar and soluble protein as photosynthesis products increased first and then decreased with the increase of exogenous selenium concentration.The results of exogenous selenium application on selenium uptake by oats showed that both exogenous selenium application methods increased the selenium content of oat plants,and the selenium content of each organ was significantly positively correlated with the concentration of exogenous selenium application.The correlation coefficient?R?between selenium content and root,stem,leaf,ear and grain of oats were:0.991,0.818,0.98,0.969,0.991;the amount of selenium applied to the roots was related to the root,stem,leaf,ear and grain of oats.The coefficients?R?are:0.856,0.947,0.991,0.982,0.95.The roots and leaves were the highest in the roots and foliar application of exogenous selenium.The selenium transfer coefficients of the two selenium application methods increased gradually with the increase of exogenous selenium application concentration,but the selenium transfer coefficient of root application was significantly lower than that of foliar application,and the difference was 2.46 times.Selenium utilization rate increased first and then decreased with the increase of exogenous selenium concentration.When the concentration of exogenous selenium was too high,it would cause toxic effects on oat plants,and the selenium utilization rate decreased.The optimum application rate of exogenous selenium in selenium-enriched oats was 15 mg·m^-22 by measuring the selenium content of oat kernels.