微塑料(MPs)是新兴的持久性污染物,重金属是典型的环境污染物,它们共存可能会加剧污染和生态风险。然而,重金属和不同类型的MPs在植物-土壤系统中的相互作用影响和相关机制尚不清楚。这项研究调查了聚乙烯MPs(PEMPs)和可生物降解的聚己二酸丁二醇酯MPs(PBATMPs)对花生中铬(Cr)吸收的不同影响,关注植物性能和根际土壤微环境。与不可降解的PE-MPs相比,可生物降解的PBATMPs对植物植物毒性产生的影响较小,土壤Cr生物有效性,和土壤特性,如pH值,CEC,DOC,还有MBC,铬污染土壤中的MBN除外。与对照相比,MPs降低了土壤pH和阳离子交换容量(CEC),而土壤可溶性碳(DOC),微生物生物质碳,MPs增加了氮(MBC和MBN)。与对照相比,土壤可利用Cr在PEMPs处理下增加11.8-177.8%,而在PBATMPs治疗下增加了5.1-156.9%。在500.0mg·kg-1Cr水平下,芽和根中的Cr含量最高,在5%的PEMPs治疗下,分别增加了53.1%和79.2%,分别,在5%的PBATMP治疗下,增加了38.3%和60.4%,分别,与对照相比。回归通径分析表明,MBC,MBN,土壤生物可利用Cr在MPs引起的土壤特性变化和花生对Cr的吸收中起着至关重要的作用。土壤细菌群落分析显示,变形杆菌,和鞘氨醇单胞菌通过抑制MPs减少,影响花生对Cr的吸收。这些结果表明,花生土壤微环境受到PBAT和PEMPs的影响,改变Cr污染土壤中Cr的生物有效性和植物对Cr的吸收。
Microplastics (MPs) are emerging persistent pollutants, and heavy metals are typical environmental pollutants, with their coexistence potentially compounding pollution and ecological risks. However, the interactive impacts and the relevant mechanisms of heavy metal and different types of MPs in plant-soil systems are still unclear. This study investigated the differential impacts of polyethylene MPs (PE MPs) and biodegradable polybutylene adipate MPs (PBAT MPs) on chromium (Cr) uptake in peanuts, focusing on plant performance and rhizosphere soil microenvironment. Compared with nondegradable PE-MPs, biodegradable PBAT MPs produced less significant influences on plant phytotoxicity, soil Cr bioavailability, and soil properties such as pH, CEC, DOC, and MBC, with the exception of MBN in Cr-contaminated soils. Compared to the control, soil pH and cation exchange capacity (CEC) decreased by MPs, while soil-soluble carbon (DOC), microbial biomass carbon, and nitrogen (MBC and MBN) increased by MPs. Compared to the control, soil-bioavailable Cr increased by 11.8-177.8% under PE MPs treatments, while increased by 5.1-156.9% under PBAT MPs treatments. The highest Cr content in shoots and roots was observed at 500.0 mg·kg-1 Cr level, which increased by 53.1% and 79.2% under 5% PE MPs treatments, respectively, as well as increased by 38.3% and 60.4% under 5% PBAT MPs treatments, respectively, compared with the control. The regression path analysis indicated that pH, MBC, MBN, and soil-bioavailable Cr played a vital role in the changes of soil properties and Cr uptake by peanuts induced by MPs. Soil bacterial community analysis revealed that Nocardioides, Proteobacteria, and Sphingomonas were reduced by the inhibition of MPs, which affected Cr uptake by peanuts. These results indicated that the peanut soil microenvironment was affected by PBAT and PE MPs, altering the Cr bioavailability and plant Cr uptake in Cr-contaminated soil.