Xu Xiang, Peng Cheng, Shao Xuechun, Gong Kailin, Zhao Xuan, Xie Wenwen, Zhang Wei, Tan Jiaqi
State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.
State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
Sci Total Environ. 2024 Dec 20;957:177669. doi: 10.1016/j.scitotenv.2024.177669. Epub 2024 Nov 29.
Biodegradable microplastics (BMPs) may impact the environmental fate and ecotoxicity of Cd, but the effect mechanism in soil-plant system remain poorly understood. This study investigated the impact of BMPs (poly(lactic acid) (PLA) and poly(butylene adipate terephthalate) (PBAT) microplastics) on the Cd toxicity, translocation, transformation, and metabolome in lettuce (Lactuca sativa L.) by pot experiments. The results show that co-exposure to BMPs and Cd synergistically inhibited the shoot growth. 0.2 % PLA MPs enhanced but 2.5 % PLA MPs inhibited the photosynthesis; however, the dose of PBAT MPs was negatively correlated with the content of chlorophyll a. Moreover, the presence of 2.5 % PBAT MPs increased the nitrate content of leaves by 9.5 % compared to single Cd exposure. The partial least squares path model (PLS-PM) indicates that BMPs exacerbated the inhibitory effects of Cd on lettuce growth. PLA MPs enhanced K, Ca, Cu, and Zn accumulation in root stele, whereas PBAT MPs promoted Fe and Mn enrichment in epidermis. Furthermore, co-exposure resulted in higher inorganic and water-soluble Cd proportions in shoots. PLA MPs elevated Cd contents in cell wall fractions of both roots and shoots, while PBAT MPs increased Cd contents in shoot cell walls and root cells and soluble Cd ratio in shoots. BMPs enhanced Cd toxicity and bioaccumulation by downregulating the expression of ABC transporters and phenylpropanoid biosynthesis pathways, and the relative abundance of related metabolites.
可生物降解微塑料（BMPs）可能会影响镉在环境中的归宿和生态毒性，但在土壤-植物系统中的作用机制仍知之甚少。本研究通过盆栽试验，研究了BMPs（聚乳酸（PLA）和聚己二酸对苯二甲酸丁二醇酯（PBAT）微塑料）对生菜（Lactuca sativa L.）中镉毒性、转运、转化和代谢组的影响。结果表明，BMPs与镉共同暴露会协同抑制地上部生长。0.2%的PLA微塑料增强了光合作用，但2.5%的PLA微塑料抑制了光合作用；然而，PBAT微塑料的剂量与叶绿素a含量呈负相关。此外，与单一镉暴露相比，2.5%的PBAT微塑料使叶片硝酸盐含量增加了9.5%。偏最小二乘路径模型（PLS-PM）表明，BMPs加剧了镉对生菜生长的抑制作用。PLA微塑料增强了根中柱中钾、钙、铜和锌的积累，而PBAT微塑料促进了表皮中铁和锰的富集。此外，共同暴露导致地上部无机镉和水溶性镉的比例更高。PLA微塑料提高了根和地上部细胞壁组分中的镉含量，而PBAT微塑料增加了地上部细胞壁和根细胞中的镉含量以及地上部可溶性镉比例。BMPs通过下调ABC转运蛋白和苯丙烷生物合成途径的表达以及相关代谢物的相对丰度，增强了镉的毒性和生物累积。
