Preparation Of A Plant Barrier Agent And Study Of Its Alleviating Effect To Soybean Seedings Under Cadmium Stress

The optimum barrier concentration of biostimulant,lanthanum chloride and sodium silicate was determined by the method of singly spraying biostimulant,lanthanum chloride and sodium silicate on soybean seedlings from the hydroponics experiment.The optimum concentration of compound was determined by response surface analysis,and spraying it on soybean seedlings under cadmium stress,the effect of the agent on the soybean seedlings was analyzed.The conclusions are as follows:(1)Under the condition of 10 mg/L Cd2+,the use of plant barrier agent to spray soybean seedlings could reduce the cadmium content in the stem and leaf of soybean seedlings.The isolation rate of cadmium in the stems of soybean seedlings for 9 days,12 days and 15 days were 12.25%,19.87%and 21.69%,and the isolation rates of cadmium in leaves were 17.89%,19.52%and 21.34%,respectively.(2)The application of biotin to soybean seedlings under cadmium stress could reduce the MDA content of the membrane lipid peroxidation products and improve the activity of antioxidant enzyme SOD,CAT and POD.The content of MDA in the leaves of soybean seedlings for 15 days was reduced from 0.1867 umol/g Fw to 0.17 umol/g Fw,and the activity of SOD was increased from 383.7 U/min/g Fw to 415.39 U/min/g Fw,and CAT activity was raised from 770 to 798.(3)Under the condition of 10 mg/L Cd2+,the content of cadmium in the root cell wall of soybean seedlings was increased by 26.98%after spraying the agent on cultivate seedlings for 15 days.The cadmium content of the organelle components and water-soluble components decreased by 5.99%and 11.34%compared with the control group.The cadmium content in the stem cell wall increased by 23.46%,and that in the organelle and water-soluble components reduced by 14.37%and 8.08%.The cadmium content in cell wall of leaves increased by 14.37%,while cadmium content in organelle and water-soluble components decreased by 5.31%and 7.59%.Plant barrier agents can effectively immobilized Cd in cell walls to reduce the toxicity to cells.(4)The barrier agent used in this study can convert the active cadmium in plant cells into inert cadmium,reducing the activity and toxicity of cadmium and alleviates the damage of cadmium toxicity to soybean seedlings.