Exploring the ameliorative effects of brassinolide on microplastic-induced stress in the rhizosphere microecology of Pinellia ternata

Microplastics (MP) are found to exist in various environmental media because of their small particle size, large quantity and difficult decomposition. Farmland soil is regarded as a major pool and source of MP. Inevitably, the chemical properties and microbial community of soil will be impacted when the MP enters the soil. Brassinolide (BR) has been shown to be an ameliorator of the adverse effect of MP on the development of Pinellia ternata . However, the potential impact of BR applications on the rhizosphere microecology of P. ternata under the interference of MP has not been researched. In the present study, P. ternata was used as test plant to study the influence of foliar BR application and soil MP interference on its root characteristics, soil enzyme activity, microbial community, and soil physical and chemical properties. In comparison with CK, the root length in the BR treatment and the combined treatment was significantly decreased by 22.8% and 35.8% respectively. As compared to the MP group, the combined treatment decreased catalase activity by 12.5% and increased urease activity by 15.8%. The combined treatment reduced pathogenic bacteria to some extent and improved the adverse effects caused by MP. The above results revealed that BR had some remediation potential in microbial community composition and soil enzyme activity under MP pollution. The purpose of this study is to understand the effects of MP on agricultural soil quality and remediation measures.