College of Resources, Sichuan Agricultural University, Chengdu 611130, Sichuan, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu 611130, Sichuan, China.
School of Agriculture and Environment, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
Sci Total Environ. 2024 Dec 10;955:176831. doi: 10.1016/j.scitotenv.2024.176831. Epub 2024 Oct 11.
The simultaneous presence of microplastics (MPs) and cadmium (Cd) in soil environments has raised concerns regarding their potential interactive effects on soil-plant ecosystems. This study explores how polyethylene (PE) at concentrations of 0.5 % (w/w), 1 % (w/w), and 2 % (w/w), and Cd at concentrations of 3 mg kg and 12 mg kg, either alone or combined, impact soil physicochemical properties, microbial community structures, and bok choy growth through a 40-day pot experiment. Our findings reveal that the addition of 2 % (w/w) PE significantly increased soil organic carbon (SOC). However, when 2 % PE coexisted with Cd, SOC levels decreased, potentially due to a reduction in enzyme activity (β-1,4-glucosidase). PE increased the proportion of 1-2 mm soil aggregates, while the coexistence of 2 % PE and Cd significantly increased the content of soil aggregates larger than 2 mm. The coexistence of PE and Cd increased available potassium (AK) in the soil by approximately 13 % to 41 %. Regarding bok choy growth, the aboveground biomass under 2 % PE was approximately 210 % of that under 0.5 % PE, possibly because of the enhancement in soil nutrients. The presence of Cd, however, reduced the chlorophyll content of bok choy by approximately 18 % to 34 %. Notably, the coexistence of high PE concentration (2 % w/w) and low Cd concentration (3 mg kg) resulted in the highest aboveground biomass among all coexistence treatments. Furthermore, the addition of PE and Cd significantly altered the structure of soil bacterial and fungal communities, with fungi showing a greater response. Bacteria were significantly associated with soil inorganic N content and plant growth. This study provides new insights into the interactions of microplastics and Cd within microbial-soil-plant systems.
同时存在于土壤环境中的微塑料（MPs）和镉（Cd）引起了人们对它们对土壤-植物生态系统潜在交互影响的关注。本研究通过 40 天的盆栽实验，探讨了浓度为 0.5%（w/w）、1%（w/w）和 2%（w/w）的聚乙烯（PE）以及浓度为 3 mg kg 和 12 mg kg 的 Cd 单独或联合作用对土壤理化性质、微生物群落结构和白菜生长的影响。我们的研究结果表明，添加 2%（w/w）PE 显著增加了土壤有机碳（SOC）。然而，当 2%PE 与 Cd 共存时，SOC 水平下降，这可能是由于酶活性（β-1,4-葡萄糖苷酶）降低所致。PE 增加了 1-2mm 土壤团聚体的比例，而 2%PE 和 Cd 的共存显著增加了大于 2mm 的土壤团聚体含量。PE 共存增加了土壤有效钾（AK）含量约 13%至 41%。关于白菜生长，2%PE 下的地上生物量约为 0.5%PE 下的 210%，这可能是由于土壤养分的增强。然而，Cd 的存在使白菜的叶绿素含量降低了约 18%至 34%。值得注意的是，高浓度 PE（2%w/w）和低浓度 Cd（3mg kg）共存处理导致地上生物量最高。此外，PE 和 Cd 的添加显著改变了土壤细菌和真菌群落的结构，真菌的反应更大。细菌与土壤无机 N 含量和植物生长显著相关。本研究为微塑料和 Cd 在微生物-土壤-植物系统中的相互作用提供了新的见解。
