Lozano Yudi M, Rillig Matthias C
Plant Ecology, Institute of Biology, Freie Universität Berlin, Berlin, Germany.
Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany.
Front Plant Sci. 2022 Aug 8;13:965576. doi: 10.3389/fpls.2022.965576. eCollection 2022.
Microplastics affect plants and soil biota and the processes they drive. However, the legacy effect of microplastics on plant-soil feedbacks is still unknown. To address this, we used soil conditioned from a previous experiment, where grew with 12 different microplastic types (conditioning phase). Here, we extracted soil inoculum from those 12 soils and grew during 4 weeks a native and a range-expanding plant species in soils amended with this inoculum (feedback phase). At harvest, plant biomass and root morphological traits were measured. Films led to positive feedback on shoot mass (higher mass with inoculum from soil conditioned with microplastics than with inoculum from control soil). Films may decrease soil water content in the conditioning phase, potentially reducing the abundance of harmful soil biota, which, with films also promoting mutualist abundance, microbial activity and carbon mineralization, would positively affect plant growth in the feedback phase. Foams and fragments caused positive feedback on shoot mass likely positive effects on soil aeration in the conditioning phase, which could have increased mutualistic biota and soil enzymatic activity, promoting plant growth. By contrast, fibers caused negative feedback on root mass as this microplastic may have increased soil water content in the conditioning phase, promoting the abundance of soil pathogens with negative consequences for root mass. Microplastics had a legacy effect on root traits: had thicker roots probably for promoting mycorrhizal associations, while had reduced root diameter probably for diminishing pathogenic infection. Microplastic legacy on soil can be positive or negative depending on the plant species identity and may affect plant biomass primarily root traits. This legacy may contribute to the competitive success of range-expanding species positive effects on root mass (foams) and on shoot mass (PET films). Overall, microplastics depending on their shape and polymer type, affect plant-soil feedbacks.
微塑料会影响植物和土壤生物群落及其驱动的过程。然而，微塑料对植物 - 土壤反馈的遗留效应仍然未知。为了解决这个问题，我们使用了先前实验处理过的土壤，在该实验中，植物与12种不同类型的微塑料一起生长（预处理阶段）。在这里，我们从这12种土壤中提取土壤接种物，并在添加了这种接种物的土壤中种植一种本地植物和一种正在扩张分布范围的植物物种达4周（反馈阶段）。在收获时，测量了植物生物量和根系形态特征。薄膜对地上部生物量产生了正反馈（与来自对照土壤接种物相比，来自用微塑料处理过的土壤接种物的植物地上部生物量更高）。薄膜可能在预处理阶段降低土壤含水量，潜在地减少有害土壤生物的数量，而薄膜也促进互利共生生物数量、微生物活性和碳矿化，这会在反馈阶段对植物生长产生积极影响。泡沫和碎片对地上部生物量产生正反馈，可能是因为在预处理阶段对土壤通气性有积极影响，这可能增加了互利共生生物和土壤酶活性，促进了植物生长。相比之下，纤维对根生物量产生负反馈，因为这种微塑料可能在预处理阶段增加了土壤含水量，促进了土壤病原体的数量，对根生物量产生负面影响。微塑料对根系性状有遗留效应：[某种植物]根系可能更粗，这可能是为了促进菌根共生，而[另一种植物]根系直径减小，可能是为了减少病原体感染。微塑料对土壤的遗留效应可能是正的或负的，这取决于植物物种的特性，并且可能主要通过根系性状影响植物生物量。这种遗留效应可能有助于正在扩张分布范围的物种在竞争中取得成功，因为对根生物量（泡沫）和地上部生物量（PET薄膜）有积极影响。总体而言，微塑料根据其形状和聚合物类型，会影响植物 - 土壤反馈。
