Response Of Rhizosphere Soil Microorganisms Of Lespedeza Sativa To Different Pb Concentrations

Desert grassland refers to the natural ecosystem of arid organisms in the transition from continental grassland to desert zone.Its ecological environment is relatively fragile.High concentration of heavy metal lead(PB)will have a certain impact on the soil environment,and then affect the Soil Microenvironment of grassland plant roots,In order to explore the effects of different lead concentrations on the dominant plant of Lespedeza angustifolia in desert grassland,this study selected Lespedeza angustifolia in desert grassland around Gaoshawo Industrial Park as the research object according to the previous research results of the research group,and set up 30 sample plots to measure the lead concentration under different five lead concentration gradients(?:0.87;?:1.87;?:2.68;?:4.08;?:6.42)The effects of heavy metal lead on the physical and chemical properties of Rhizosphere Soil and the species diversity and distribution of rhizosphere soil microorganisms in desert grassland were analyzed The main conclusions are as follows:(1)There were significant differences in plant indexes under different Pb concentrations,including no significant difference in soil water content,significant differences in plant height and leaf area,significant differences in root activity under the five gradients,and the overall trend was first increased and then decreased Under different Pb concentrations,N,P and K uptake of Bougainvillea was different,and the difference was significant(P<0.05).(2)There were significant differences in the physical and chemical properties of Rhizosphere Soil under different Pb concentrations;The soil water content increased with the increase of Pb concentration,and the pH value fluctuated between 8.49 and 8.84;With the change of Pb concentration gradient,soil organic carbon increased at first and then decreased.Total nitrogen had the highest value under gradient ?,total potassium and available phosphorus had the highest value,and then increased and then decreased with the increase of Pb concentration under gradient ?;The highest values of total phosphorus and alkali hydrolyzable nitrogen were found in the third gradient,and the highest values of available potassium were much higher in the high concentration than in the low concentration;The activities of urease and sucrase were the highest under the gradient of ?,and alkaline phosphatase was the highest under the gradient of ?.these three enzymes increased first and then decreased with the change of Pb concentration gradient;The activity of catalase did not fluctuate in the first four concentration gradients,indicating that the appropriate concentration of Pb can promote the activity of catalase,and high concentration can inhibit the activity of catalase to a certain extent.(3)The 1909 out of 5 gradients belong to 377 species of 336 genera,193 families,60 classes,124 orders,22 phyla,and the top 10 phyla with high relative richness belong to bacteria species.Based on the natural conditions of poor soil nutrients and single vegetation in desert grassland,there are significant differences in the analysis of rhizosphere soil microorganisms in the genus level.To sum up,high concentrations of heavy metal lead(Pb)have different effects on soil physical and chemical properties,generally speaking,low concentrations promote,high concentrations inhibit;The species and distribution of soil microorganisms in desert steppe are greatly affected by soil environmental factors,which are mainly reflected in soil water content,soil pH,total nitrogen and soil organic carbon;There were significant differences in the analysis results at the microbial genus level.