聚乙烯与镉胁迫下枯草芽孢杆菌与沼泽红假单胞菌对茶苗安全生长的影响OA

To elucidate the remediation potential and underlying mechanisms of a microbial composite agent against polyethylene(PE)microplastic and cadmium(Cd)co-contamination in tea garden soils,a pot experiment was conducted using Camellia sinensis cv.'Longjing 43'seedlings.Soil samples were spiked with PE particle suspension and CdCl2·5H2O to simulate co-contamination stress.A microbial composite agent composed of Bacillus subtilis and Rhodopseudomonas palustris with a 1:1 viable cell ratio was subsequently applied to explore the effects of different application concentrations on soil biological activity,microbial community structure,as well as tea seedling morphology,Cd accumulation,stress resistance,photosynthetic parameters,and related gene expression.The results show that the application of the composite agent significantly enhanced soil enzyme activities,promoted the immobilization of available Cd,optimized the microbial community structure,and increased the abundance of beneficial microbial groups.At the plant level,the agent reduced Cd translocation to tea leaves,alleviated oxidative damage,and restored photosynthetic performance and antioxidant defense in tea seedlings.Expressions of genes related to α-linolenic acid metabolism,phenylalanine metabolism,and fatty acid catabolism were up-regulated,indicating the activation of stress-adaptive metabolic pathways.These findings indicate that the microbial composite agent can effectively mitigate oxidative damage and heavy metal toxicity induced by PE-exacerbated Cd stress via regulating the soil environment and the physiological and molecular networks in tea plants in a concentration-dependent manner.This study provided a theoretical basis and technical support for the bioremediation of microplastic and heavy metal co-contamination in tea garden soils and for the safe production of tea plants.