Effect Of Photosynthetic Bacteria On Growth And Quality Of Astragalus Membranaceus

Objective:The present study investigated to explore the effects of different concentrations of Photosynthetic Bacteria（PSB）and Rhodopseudomonas palustris on wild imitation and cultured Astragalus membranaceus,the growth indexes of A.membranaceus under different planting methods,the contents of active components,nutrient elements and heavy metal residues in roots,the physicochemical properties of rhizosphere soil and soil enzyme activities were determined.To explore the effects of PSB and R.palustris on the quality and soil of wild imitation and cultured A.membranaceus,in order to provide a theoretical basis for PSB and R.palustris as biological fertilizer to improve the quality of A.membranaceus.Methods:Part 1:Two year old wild imitation and cultured A.membranaceus were divided into plots,and different concentrations of PSB and R.palustris were injected into the root and sprayed.After harvesting,By measuring the growth indexes of Astragalus（mean root diameter,root fresh weight,root dry weight and root length）and using HPLC method,the contents of Astragalus IV and five flavonoids（Calycosin-7-glucoside,Ononin,Isomucronulatol 7-O-glucoside,methylnissolin-3-O-glucoside and Isomucronulatol 7-O-beta-glucoside）in 126 A.membranaceus samples were determined,analyzed and compared two kinds of bacteria with different concentrations on two different cultivation methods,the effects of growth and active component content of A.membranaceus membranaceus.Part 2:Through the determination of nutrient elements（N,P,K,Ca,Mg,Fe,Mn,Cu,Zn,Se）content and heavy metal elements（Pb,Cd,Hg）residues in 126 A.membranaceus samples,analysis was conducted to compare the changes of nutrient elements and heavy metal contents in the root of A.membranaceus root under different cultivation methods.Part 3:The physicochemical properties（soil p H,organic matter,total nitrogen,total phosphorus and total potassium）and biological properties（soil sucrase,urease and alkaline phosphatase）of 126 A.membranaceus rhizosphere soil samples were determined to determine whether the two bacteriotics had an effect on soil fertility.The correlation analysis was carried out based on the results of the first two parts to determine the relationship between soil fertility and plants.Part 4:Pot experiment was conducted to compare the growth and active component content of A.membranaceus treated with PSB and R.palustris.Combined with the first three parts of experiments,comprehensive evaluation was made on which bacteria treated with A.membranaceus quality more.Results:Part 1:SPSS analysis results showed that the root fresh weight and root length were the highest in the P₃ treatment group,and the root diameter was the largest in the M₂treatment group.The content of active ingredients in wild imitation A.membranaceus root was higher than cultured A.membranaceus root,and the content of astragalus agaloside in wild imitation A.membranaceus root was significantly increased under the treatment of two kinds of bacteria.The content of astragaloside IV in root of A.membranaceus root of cultured A.membranaceus s root increased significantly under the treatment of PSB.The contents of Ononin and Isomucronulatol 7-O-glucoside in wild imitation A.membranaceus root were increased under the treatment of PSB,while the content of Calycosin-7-glucoside was significantly increased under the treatment of R.palustris.The contents of Calycosin-7-glucoside and Isomucronulatol 7-O-beta-glucoside in the root of A.membranaceus plantarum were increased under the treatment of PSB,while the contents of methylnissolin-3-O-glucoside and Isomucronulatol 7-O-beta-glucoside were significantly increased under the treatment of R.palustris.The growth and effective components of astragalus were improved by the two bacterials,and the optimal dilution was 200 times.Part 2:The content of macrotrophic elements in wild imitation A.membranaceus root was lower than cultured A.membranaceus root,but the content of trace elements and heavy metal residues were higher than cultured A.membranaceus root.After applying the two bacteriotics,the contents of a large number of elements in wild imitation A.membranaceus root changed little,while the contents of N and K elements in cultured A.membranaceus root increased significantly.The content of trace elements in A.membranaceus root increased significantly after the application of two bacteriotics,while the content of heavy metal elements decreased significantly.Considering the effect of PSB on A.membranaceus,the optimal dilution was 200 times.Part 3:The two bacteria significantly reduced rhizosphere soil p H,significantly increased the content of organic matter,soil enzyme activity also significantly increased.The PSB had a greater effect on the wild imitation rhizosphere soil,and the R.palustris had a greater effect on cultured A.membranaceus rhizosphere soil.The correlation analysis of various indexes of plants and rhizosphere soil showed that there were significant differences between sucrase and total P,significant differences between total P content and some nutrient elements in A.membranaceus root,and significant differences between trace elements and active components in A.membranaceus root.The PSB had a great effect on the soil fertility of wild imitation soil,and the R.palustris had a great effect on the soil fertility of cultured A.membranaceus.Part 4:The PSB diluted 200 times spray treatment group had the greatest effect on the growth rate of A.membranaceus,which was consistent with the conclusion of the first part.Based on the influence on the accumulation of active components,the accumulation of A.membranaceus under PSB treatment was larger than that of R.palustris.The glucoside of calycoflavone was consistent with the experiment in the first part,which decreased but had no significant difference under the treatment of the two bacterials.The other four flavonoids had significant increase,and also decreased but had no significant difference.Conclusion:In this study,the growth,active component content,nutrient element content,heavy metal residue and physicochemical and biological properties of rhizosphere soil of 126 A.membranaceus samples were measured and correlation analysis was carried out.It was found that the two photosynthetic bacteria had positive effects on various indexes of A.membranaceus.In terms of the content of active components,PSB had greater effect on the active components in wild imitation and cultured A.membranaceus root.Only considering the influence of nutrient elements,it was concluded that R.palustris had a greater effect on wild imitation A.membranaceus,and PSB had a greater effect on cultured A.membranaceus.From the point of view of reducing heavy metal content,whether it is wild imitation or cultured A.membranaceus,PSB has greater effect on reducing heavy metal content.Under the factors of improving soil fertility,R.palustris had a greater effect on soil fertility of cultured A.membranaceus,and PSB had a greater effect on soil fertility of wild imitation A.membranaceus.