Abstract：
As an exogenous carbon input, microplastics (MPs), especially biodegradable MPs, may significantly disrupt soil microbial communities and soil element cycling (CNPS cycling), but few studies have focused on this. Here, we focused on assessing the effects of conventional low-density polyethylene (LDPE), biodegradable polybutylene adipate terephthalate (PBAT), and polylactic acid (PLA) MPs on rhizosphere microbial communities and CNPS cycling in a soil-soybean system. The results showed that PBAT-MPs and PLA-MPs were more detrimental to soybean growth than LDPE-MPs, resulting in a reduction in shoot nitrogen (14.05% and 11.84%) and shoot biomass (33.80% and 28.09%) at the podding stage. In addition, dissolved organic carbon (DOC) increased by 20.91% and 66.59%, while nitrate nitrogen (NO3--N) significantly decreased by 56.91% and 69.65% in soils treated with PBAT-MPs and PLA-MPs, respectively. PBAT-MPs and PLA-MPs mainly enhanced copiotrophic bacteria (Proteobacteria) and suppressed oligotrophic bacteria (Verrucomicrobiota, Gemmatimonadota, etc.), increasing the abundance of CNPS cycling-related functional genes. LDPE-MPs tended to enrich oligotrophic bacteria (Verrucomicrobiota, etc.) and decrease the abundance of CNPS cycling-related functional genes. Correlation analysis revealed that MPs with different degradation properties selectively affected the composition and function of the bacterial community, resulting in changes in the availability of soil nutrients (especially NO3--N). Redundancy analysis further indicated that NO3--N was the primary constraining factor for soybean growth. This study provides a new perspective for revealing the underlying ecological effects of MPs on soil-plant systems.
摘要：
作为外源碳输入，微塑料（MPs），特别是可生物降解的国会议员，可能会显著破坏土壤微生物群落和土壤元素循环(CNPS循环)，但是很少有研究关注这一点。这里,我们专注于评估传统低密度聚乙烯(LDPE)的影响，可生物降解的聚己二酸对苯二甲酸丁二醇酯（PBAT），和聚乳酸（PLA）MPs对土壤-大豆系统中根际微生物群落和CNPS循环的影响。结果表明,与LDPE-MPs相比,PBAT-MPs和PLA-MPs对大豆生长的影响更大,导致播散阶段的芽氮（14.05％和11.84％）和芽生物量（33.80％和28.09％）减少。此外,溶解有机碳(DOC)分别增长20.91%和66.59%,在PBAT-MPs和PLA-MPs处理的土壤中，硝酸盐氮（NO3--N）显着降低了56.91％和69.65％，分别。PBAT-MPs和PLA-MPs主要增强共营养细菌（变形杆菌）和抑制的寡营养细菌（Verrucomicrobiota，Gemmatimonadota,等。),增加CNPS循环相关功能基因的丰度。LDPE-MPs倾向于富集寡营养细菌(Verrucomicrobiota，等。)并降低CNPS循环相关功能基因的丰度。相关分析表明,不同降解性质的MPs选择性地影响细菌群落的组成和功能,导致土壤养分(尤其是NO3--N)的有效性发生变化。冗余分析进一步表明，NO3--N是大豆生长的主要制约因素。本研究为揭示MPs对土壤-植物系统的潜在生态效应提供了新的视角。
