Abstract：
Mulching to conserve moisture has become an important agronomic practice in saline soil cultivation, and the effects of the dual stress of salinity and microplastics on soil microbes are receiving increasing attention. In order to investigate the effect of polyethylene microplastics on the microbial community of salinized soils, this study investigated the effects of different types (chloride and sulphate) and concentrations (weak, medium, and strong) of polyethylene (PE) microplastics (1% and 4% of the dry weight mass of the soil sample) on the soil microbial community by simulating microplastic contamination in salinized soil environments indoors. The results showed that:PE microplastics reduced the diversity and abundance of microbial communities in salinized soils and were more strongly affected by sulphate saline soil treatments. The relative abundance of each group of bacteria was more strongly changed in the sulphate saline soil treatment than in the chloride saline soil treatment. At the phylum level, the relative abundance of Proteobacteria was positively correlated with the abundance of fugitive PE microplastics, whereas the relative abundances of Bacteroidota, Actinobacteriota, and Acidobacteria were negatively correlated with the abundance of fugitive PE microplastics. At the family level, the relative abundances of Flavobacteriaceae, Alcanivoracaceae, Halomonadaceae, and Sphingomonasceae increased with increasing abundance of PE microplastics. The KEGG metabolic pathway prediction showed that the relative abundance of microbial metabolism and genetic information functions were reduced by the presence of PE microplastics, and the inhibition of metabolic functions was stronger in sulphate saline soils than in chloride saline soils, whereas the inhibition of genetic information functions was weaker than that in chloride saline soils. The secondary metabolic pathways of amino acid metabolism, carbohydrate metabolism, and energy metabolism were inhibited. It was hypothesized that the reduction in metabolic functions may have been caused by the reduced relative abundance of the above-mentioned secondary metabolic pathways. This study may provide a theoretical basis for the study of the effects of microplastics and salinization on the soil environment under the dual pollution conditions.
摘要：
覆盖保存水分已成为盐渍土栽培的重要农艺实践,盐分和微塑料双重胁迫对土壤微生物的影响日益受到重视。为了研究聚乙烯微塑料对盐渍化土壤微生物群落的影响,这项研究调查了不同类型(氯化物和硫酸盐)和浓度(弱，中等,和强）的聚乙烯（PE）微塑料（土壤样品干重质量的1％和4％）对土壤微生物群落通过模拟室内盐渍化土壤环境中的微塑料污染。结果表明:PE微塑料降低了盐渍化土壤中微生物群落的多样性和丰度,受硫酸盐盐渍土处理的影响更大。与氯化物盐渍土处理相比，硫酸盐盐渍土处理中每组细菌的相对丰度变化更大。在门一级，变形杆菌的相对丰度与挥发性PE微塑料的丰度呈正相关，而拟杆菌的相对丰度，放线菌,酸性细菌和酸性细菌与挥发性PE微塑料的丰度呈负相关。在家庭层面,黄杆菌科的相对丰度，鳄梨科，Halomonadaceae，和Sphingomonasceae随着PE微塑料丰度的增加而增加。KEGG代谢途径预测表明，PE微塑料的存在降低了微生物代谢和遗传信息功能的相对丰度，硫酸盐盐渍土壤对代谢功能的抑制作用强于氯化物盐渍土壤，而对遗传信息功能的抑制作用弱于氯盐渍土。氨基酸代谢的次级代谢途径，碳水化合物代谢，能量代谢受到抑制。假设代谢功能的降低可能是由上述次级代谢途径的相对丰度降低引起的。本研究可为研究微塑料和盐渍化对双重污染条件下土壤环境的影响提供理论依据。
