Microplastic pollution and biological invasion, as two by-products of human civilization, interfere the ecological function of aquatic ecosystem. The restoration of aquatic vegetation has been considered a practical approach to offset the deterioration of aquatic ecosystem. However, a lack of knowledge still lies in the species selection in the revegetation when confronting the interference from microplastic pollution and exotic counterpart. The present study subjected the native submerged species, Hydrilla verticillata and its exotic confamilial, Elodea nuttallii to the current and future scenarios of polyamide microplastic pollution. The plant performance proxies including biomass and ramet number were measured. We found that the native H. verticillata maintained its performance while the exotic E. nuttallii showed decreases in biomass and ramet number under severest pollution conditions. The restoration of native submerged plant such as H. verticillata appeared to be more effective in stabilizing aquatic vegetation in the scenario of accelerating microplastic pollution. In order to explore the underlying driving mechanism of performance differentiation, stress tolerance indicators for plants, sediment enzymatic activity and sediment fungal microbiome were investigated. We found that polyamide microplastic had weak effects on stress tolerance indicators for plants, sediment enzymatic activity and sediment fungal diversity, reflecting the decoupling between these indicators and plant performance. However, the relative abundance of sediment arbuscular mycorrhizal fungi for H. verticillata significantly increased while E. nuttallii gathered “useless” ectomycorrhizal fungi at the presence of severest polyamide microplastic pollution. We speculate that the arbuscular mycorrhizal fungi assisted the stabilization of plant performance for H. verticillata with exposure to the severest polyamide microplastic pollution.

中文翻译：

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本地沉水植物 Hydrilla verticillata 在暴露于聚酰胺微塑料污染后的表现优于其外来物种：对湿地植被恢复的影响和潜在的驱动机制


微塑料污染和生物入侵作为人类文明的两大副产品，干扰着水生生态系统的生态功能。恢复水生植被被认为是抵消水生生态系统恶化的实用方法。然而，在面对微塑料污染和外来生物污染的干扰时，重新植被中的物种选择仍然缺乏知识。本研究对本地沉水物种 Hydrilla verticillata 及其外来亲属 Elodea nuttallii 进行了聚酰胺微塑料污染的当前和未来情景。测量了包括生物量和分株数在内的植物性能指标。我们发现，在最严重的污染条件下，本地 H. verticillata 保持了其性能，而外来的 E. nuttallii 则表现出生物量和分株数量的减少。在微塑料污染加速的情况下，恢复本地沉水植物（如 H. verticillata）似乎在稳定水生植被方面更有效。为了探究性能差异的潜在驱动机制，研究了植物的耐逆性指标、沉积物酶活性和沉积物真菌微生物组。我们发现聚酰胺微塑料对植物的耐逆性指标、沉积物酶活性和沉积物真菌多样性的影响较弱，反映了这些指标与植物性能之间的脱钩。然而，H. verticillata 的沉积物丛枝菌根真菌的相对丰度显着增加，而 E. nuttallii 在最严重的聚酰胺微塑料污染存在的情况下收集了“无用的”外生菌根真菌。 我们推测，丛枝菌根真菌有助于在暴露于最严重的聚酰胺微塑料污染的情况下稳定轮枝 H. verticillata 的植物性能。