铅污染土壤中解磷菌对玉米根际土壤性质和微生物群落结构的影响OA北大核心CSTPCD

[Objective]To explore the effects of phosphate-solubilizing bacteria(PSB)and their fermentation products on the properties of maize(Zea mays L.)rhizosphere soil and the composition and diversity of microbial community in lead-contaminated soil.[Method]Based on the screening of Klebsiella pasteurii with lead-resistant and phosphate-solubilizing function,corn was cultivated in lead-contaminated soil by pot experiment.LB medium,supernatant(bacterial secretion),bacterial solution(only bacterial cells)and fermentation broth(supernatant+bacterial cells)were applied to the rhizosphere,and sterile water control was set to explore the effects of phosphate-solubilizing bacteria on the physical and chemical properties of rhizosphere soil and microbial community structure.[Result]The supernatant,bacterial liquid and fermentation liquid of K.baumannii had no significant effect on the diversity of bacterial community in maize rhizosphere,while the bacterial liquid significantly increased the Shannon index and Chao index of soil fungal community.The supernatant,bacterial liquid and fermentation liquid of the strain increased the relative abundances of heavy metal-resistant microbial groups such as Bacteroidetes and Actinobacteria,while the supernatant and fermentation liquid increased the abundances of Proteobacteria and Mortierellomycota.The supernatant increased the relative abundances of Sphingomonas,Blastococcus,Bradyrhizobium and Archaeorhizomyces.In addition,Pearson correlation analysis of differential genera in the maize rhizosphere soil showed that there were positive correlations among 7 groups of differential genera,which revealed that different microbial genera tended to form mutually beneficial symbiotic relationships.The supernatant,bacterial liquid and fermentation liquid of the strain significantly increased the activities of soil acid phosphatase(Acp).Among them,the Acp activity of maize rhizosphere soil in the fermentation liquid treatment group was the highest(574.44 mg/g,24-1).The application of supernatant and bacterial liquid significantly increased the content of alkali-hydrolyzed nitrogen(AN)in the rhizosphere soil,which was 47.4%and 39.5%higher than that of the control,respectively.The three treatment groups significantly reduced the soil pH value.Through redundancy analysis(RDA),it was found that soil AN,Acp,pH value and available phosphorus(AP)were the main factors affecting the microbial community structure.[Conclusion]This study reveales that exogenous application of PSB and their fermentation products was beneficial to improving the fertility of lead-contaminated soil,and affectes the composition and structure of soil microbial community,which provides a theoretical basis for inoculating PSB and improving soil nutrients and soil microbial community structure in lead-contaminated farmland.