Abstract：
The interaction between microplastics (MPs) and cadmium (Cd) poses a threat to agricultural soil environments, and their effects on plant growth and rhizosphere microbial community functions are not yet clear. In this study, energy sorghum was used as a test plant to investigate the effects of two types of MPs, polystyrene (PS) and polyethylene (PE), at different particle sizes (13 μm, 550 μm) and concentrations (0.1%, 1% w/w), and Cd, as well as their interactions, on the growth of sorghum in a soil-cultivation pot experiment. The results showed that the combined effects of MP and Cd pollution on the dry weight and Cd accumulation rate in sorghum varied depending on the type, concentration, and particle size of the MPs, with an overall trend of increasing stress from combined pollution with increasing Cd content and accumulation. High-throughput sequencing analysis revealed that combined MP and Cd pollution increased bacterial diversity, and the most significant increase was observed in the abundance-based coverage estimator (ACE), Shannon, and Sobs indices in the 13 μm 1% PS+Cd treatment group. Metagenomic analysis based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways revealed that 19 groups of metabolic pathways, including microbial metabolism and methane metabolism, differed significantly under combined MP and Cd pollution. Hierarchical clustering results indicated that Cd treatment and combined MP and Cd treatment affected the abundances of sorghum rhizosphere soil nitrogen (N) and phosphorus (P) cycling genes and that the type of MP present was an important factor affecting N and P cycling genes. The results of this study provide a basis for exploring the toxic effects of combined MP and Cd pollution and for conducting soil environmental risk assessments.
摘要：
微塑料（MPs）和镉（Cd）之间的相互作用对农业土壤环境构成威胁，它们对植物生长和根际微生物群落功能的影响尚不清楚。在这项研究中,能量高粱被用作试验植物，以研究两种类型的MP的影响，聚苯乙烯（PS）和聚乙烯（PE），在不同的粒径(13μm，550μm)和浓度(0.1%，1%w/w)，还有Cd,以及他们的互动，高粱在土壤栽培盆栽中的生长实验。结果表明，MP和Cd污染对高粱干重和Cd积累速率的综合影响因类型而异。浓度,和国会议员的颗粒大小，随着Cd含量和积累的增加，复合污染的总体胁迫趋势增加。高通量测序分析表明，MP和Cd污染的结合增加了细菌的多样性，在基于丰度的覆盖率估计器(ACE)中观察到最显着的增加，香农,13μm1%PS+Cd处理组的Sobs指数。基于京都基因和基因组百科全书（KEGG）代谢途径的宏基因组分析显示，19组代谢途径，包括微生物代谢和甲烷代谢，在MP和Cd复合污染下差异显著。分层聚类结果表明，Cd处理以及MP和Cd联合处理影响了高粱根际土壤氮（N）和磷（P）循环基因的丰度，而MP存在的类型是影响N和P循环基因的重要因素。本研究结果为探索MP和Cd复合污染的毒性效应和进行土壤环境风险评价提供了依据。
