Here we investigated the effects of three types of microplastics (MPs), i.e., PS (P), ABS (B), PVC (V), and each with additive (MPAs) (PA, BA, and VA), on soil health, microbial community, and plant growth in two acidic and slightly alkaline soils. Incubation experiment revealed that although MPs and MPAs consistently stimulated soil nutrients and heavy metals (e.g., Mn, Cu) in weakly alkaline soils, only BA and VA led to increase in soil nutrients and heavy metals in acidic soils. This suggests distinct response patterns in the two soils depending on their initial pH. Concerning microorganisms, MPs and MPAs reduced the assembly degree of bacteria in acidic soils, with a reduction of Chloroflexi and Acidobacteriota but an increase of WPS-2 in VA. Culture experiment showed consistent positive or negative responses in radish seed germination, roots, and antioxidant activity across MPs and MPAs types in both soils, while the responses of seed heavy metals (e.g., Cr, Cd) were consistent in acidic soils but dependent on MPs and MPAs types in alkaline soils. Therefore, our study strongly suggests that the effects of MPs on soil-microbial-plant systems were highly dependent on initial soil characteristics and the types of MPs with plastic additives.

中文翻译：

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揭示两种不同 pH 值的农业土壤中添加/不添加微塑料对萝卜 (Raphanus sativus) 和微生物群的影响


在这里，我们研究了三种类型的微塑料 (MP)，即 PS (P)、ABS (B)、PVC (V) 以及每种微塑料 (MPA)（PA、BA 和 VA）对土壤健康的影响、微生物群落和植物在两种酸性和微碱性土壤中的生长。孵化实验表明，虽然MPs和MPA持续刺激弱碱性土壤中的土壤养分和重金属（如Mn、Cu），但只有BA和VA导致酸性土壤中土壤养分和重金属的增加。这表明两种土壤的响应模式不同，具体取决于它们的初始 pH 值。在微生物方面，MPs和MPA降低了酸性土壤中细菌的聚集程度，其中Chloroflexi和Acidobacteriota减少，但VA中WPS-2增加。培养实验表明，两种土壤中的 MP 和 MPA 类型对萝卜种子发芽、根系和抗氧化活性的反应一致，而种子重金属（例如 Cr、Cd）的反应在酸性土壤中是一致的，但取决于 MP和碱性土壤中的 MPA 类型。因此，我们的研究强烈表明，MP 对土壤-微生物-植物系统的影响高度依赖于初始土壤特性和含有塑料添加剂的 MP 类型。