Effects Of Different Selenium Sources On The Quality,Nutrient Absorption,Yield And Antioxidant Capacity Of Pakchoi

Effects of different selenium sources on the quality,nutrient absorption,yield and antioxidant capacity of pakchoi were studied.Set up two selenium application methods,root application and foliar application.In order to screen out the appropriate application concentration and selenium source,provide theoretical and technical basis for the production of selenium-enriched pakchoi.In order to screen out the appropriate application concentration and selenium source,provide theoretical and technical basis for the production of selenium-enriched pakchoi.Two exogenous selenium,inorganic selenium and organic selenium were selected in the experiment,and two selenium application methods were adopted,namely root application and foliar application,The results showed that:1.Root application of sodium selenite can increase the absorption of P,Ca,Mg,Fe in the shoot of pakchoi.Root application of DL-selenomethionine can increase the absorption of Ca,Mg,Fe in the shoot of pakchoi;increase the absorption of N and Mg in the shoot of pakchoi.The Se content of pakchoi shoot and root gradually increased with the increase of selenium concentration.2.When exogenous selenium is applied to the roots,all treatments of sodium selenite and DL-selenomethionine can increase the activities of antioxidant enzymes SOD,POD and CAT in the leaves of pakchoi;under sodium selenite treatment,SOD activity is highest at0.5 mg·L^-1,POD and CAT activity are highest at 0.1 mg·L^-1;under DL-selenomethionine treatment,SOD activity is highest at 0.5 mg·L^-1,POD activity is highest at 0.1 mg·L^-1,and CAT activity is highest at 2.5 mg·L^-1.highest.3.When exogenous selenium is applied to the root,when the concentration of Se is less than or equal to 1.0 mg·L^-1,sodium selenite and DL-selenomethionine can promote the growth of cabbage and increase the yield;while the concentration of Se is 2.5 mg·L^-1,both sodium selenite and DL-selenomethionine treatments can inhibit the growth of pakchoi;all treatments can increase the photosynthetic pigment content and nitrate reductase activity of pakchoi leaves.4.Root application of sodium selenite can increase the contents of free amino acids,soluble sugars,soluble proteins,flavonoids and total phenols of pakchoi leaves to varying degrees,and reduce the contents of nitrate and crude fiber;Root application of DL-Cimethionine can increase the contents of free amino acids,vitamin C,soluble sugars,and soluble proteins,flavonoids and total phenols of pakchoi leaves to varying degrees,and reduce the content of nitrates.5.Foliar application of sodium selenite can increase the absorption of N,P,K,Mg,Na in the shoot of pakchoi,and increase the absorption of N,P,Ca,Fe and Na;Foliar application of DL-selenomethionine can increase the absorption of N,P,K,Mg,Ca in the shoots of pakchoi,and increase the absorption of P,N,Ca,Na inshoot of pakchoi.Se content in the shoots of pakchoi increased gradually with the increase of selenium concentration.6.When foliar application with exogenous selenium,the treatment of sodium selenite and DL-selenomethionine,when the Se concentration is less than or equal to 30 mg·L-1,can promote the growth of pakchoi and increase the yield;All treatments can increase the photosynthetic pigment content of pakchoi leaves.7.Foliar application with sodium selenite can increase the soluble sugar,soluble protein,flavonoid and total phenol content of pakchoi leaves to varying degrees,and reduce the nitrate content;Foliar application of DL-Cimethionine can increase the content of free amino acids,soluble sugars,and soluble proteins,flavonoids and total phenols in the leaves of pakchoi cabbage to varying degrees,and reduce the content of nitrates.Comprehensive analysis showed that sodium selenite was used as the source of selenium,and the best concentration of Se in roots was 0.5 mg·L-1,which could increase the free amino acid,soluble sugar,soluble protein,light and pigment content of pakchoi leaves,promote absorption of nutrient elements,increase yield and reduce nitrate Crude fiber content;Using DL-selenomethionine as the source of selenium,the best concentration of 20 mg·L-1 of Se on the leaf surface is the best,which can increase the free amino acids,soluble protein,vitamin C,soluble sugars,flavonoids,total phenols and light of pakchoi leaves,promote absorption of nutrient elements,increase yield,and reduce nitrate content.