微塑料对费氏中华根瘤菌生理生化特性及其活化土壤难溶性磷能力的影响OA

To investigate the effects of microplastics on the physiological and biochemical properties of rhizobia and their ability to activate insoluble phosphorus in soil,Sinorhizobium fredii was selected as the test strain.The impacts of monodisperse polystyrenemicroplastics(PS-MPs)atdifferentconcentrationsonthegrowth,biofilmformation,an-tioxidant system,and phosphorus-solubilizing capacity of S.fredii were studied.The results showed that microplas-tics affected the growth of S.fredii.Treatments with 80-300 mg·L-1 PS-MPs significantly(p＜0.05)promoted bio-film formation.All PS-MPs treatments at 20-300 mg·L-1 significantly increased the contents of hydrogen peroxide(H2 O2)and soluble protein in S.fredii;however,the responses of different types of antioxidant enzymes and antiox-idant substances varied,reflecting the complexity of the antioxidant defense mechanism in S.fredii.Additionally,PS-MPs treatments at 20-300 mg·L-1 all led to a significant decrease in the content of available phosphorus in soil than that of the treatment without PS-MPs,indicating that microplastic pollution impaired the ability of S.fredii to activate insoluble phosphorus in soil.These results not only reveal the mechanism underlying the effects of microplas-tic pollution on the physiological and biochemical metabolism of S.fredii,but also provide a basis for in-depth under-standing of the biological functions of rhizobia and optimization of soil phosphorus cycling.