Effects Of Selenium And Arbuscular Mycorrhizal Fungi On Growth,Quality And Cadmium Absorption Of Talinum Paniculatum (Jacq.)Gaertn

Cd is one of the main soil pollutants,which seriously affects the growth and development of plants.Adding an appropriate amount of Se to the soil can help plant growth,increase yield,and improve quality.AMF is a beneficial microorganism that can promote plant growth and enhance plant resistance.Talinum paniculatum is a vegetable with edible,medicinal and ornamental functions.It has rich nutritional value and delicious taste.The purpose of this experiment is to study the effects of different concentrations of Cd and Se(0,2.5,5,10,20mg·kg^-1)and different types of AMF on the growth and physiological characteristics of Talinum paniculatum,and to screen out the critical Cd concentration,optimal Se concentration and AMF.At the same time,through the application of Se in the soil and inoculate AMF,the growth,quality,mineral elements and accumulation of Cd and Se of Talinum paniculatum under Cd stress were studied.The main research conclusions are as follows:1.Low concentration of Cd(0～10 mg·kg^-1)promoted the growth of Talinum paniculatum,the biomass,photosynthetic pigment content and antioxidant enzyme activity of Talinum paniculatum increased,and medium and high concentration of Cd(10～20 mg·kg^-1)inhibited its growth.The relative conductivity of Talinum paniculatum leaves increased first and then decreased;the content of soluble sugar and soluble protein increased.Talinum paniculatum have a certain accumulation capacity for Cd,and the distribution of Cd in Talinum paniculatum was:root>leaf>stem.The study believes that the Cd concentration of10 mg·kg^-1 was the critical concentration that affects the growth of Talinum paniculatum.2.Different concentrations of Se have a"low promotion and high inhibition"effect on the growth of Talinum paniculatum.Se application was beneficial to the photosynthesis of Talinum paniculatum.High concentration of Se(≥10 mg·kg^-1)significantly increased the content of photosynthetic pigments in Talinum paniculatum leaves.With the increase of Se concentration,the activities of antioxidant enzymes SOD,POD,CAT,soluble protein content increased first and then decreased;the content of Vc in the leaves of Talinum paniculatum gradually increased,and the content of soluble sugar decreased.Talinum paniculatum have a certain enrichment capacity for Se,and the distribution of Se content was:root>leaf>stem.Studies suggest that the concentration of Se of 5 mg·kg^-1 was the best concentration to promote the growth of Talinum paniculatum and improve their quality.3.The inoculated Talinum paniculatum were all infected,and the infection rate was:GM>GV>BEG167>BEG168>GMA.Inoculation of AMF was beneficial to the growth of Talinum paniculatum and the increase of biomass,and the promotion effect of BEG167 and BEG168 was more obvious.The total content of chloroplast pigment in BEG167 treatment was the highest.GV,GM and BEG167 treatments significantly increased the SOD and POD activities of Talinum paniculatum,and there was no significant difference in CAT activity between treatments.Inoculation of AMF increased the content of soluble protein and Vc in the leaves of Talinum paniculatum and reduced the content of nitrate nitrogen,but the soluble sugar content didn’t change much.Comprehensive analysis,BEG167 was the dominant strain beneficial to the growth of Talinum paniculatum.4.Cd toxicity of Talinum paniculatum was alleviated by Se and AMF alone or Se and AMF together.The growth of Talinum paniculatum resumed and the biomass increased.The chlorophyll content of Talinum paniculatum increased,photosynthesis was promoted,and photosynthetic efficiency was enhanced.At the same time,the relative conductivity of Talinum paniculatum was significantly reduced,and the activities of POD and SOD were significantly increased.The content of soluble protein,total free amino acids,Vc,total flavonoids and total phenols in Talinum paniculatum increased significantly and the quality was improved.The contents of Ca,Cu and Zn in Talinum paniculatum increased,while the contents of Mg and Fe were not affected.After Se alone,AMF alone,and Se and AMF together,the root system of Talinum paniculatum reduced the absorption of Cd,inhibited the transfer of Cd to the aboveground,and the Cd content in the aboveground decreased significantly.Comprehensive analysis,soil Se application and inoculation can promote the growth of Talinum paniculatum under Cd stress,improve its quality,and reduce the Cd content in its edible parts,especially the interaction effect of Se and AMF together.