Tire wear particles (TWPs), generated from tire abrasion, contribute significantly to environmental contamination. The toxicity of TWPs to organisms has raised significant concerns, yet their effects on terrestrial plants remain unclear. Here, we investigated the long-term impact of pristine and naturally aged TWPs on water spinach (Ipomoea aquatica) and its rhizospheric soil. The results indicated that natural aging reduced the toxicity of TWPs, as evidenced by decreased levels of polycyclic aromatic hydrocarbons (PAHs) in soil and TWPs themselves. Consequently, aged TWPs were found to enhance the plant growth and chlorophyll content, whereas pristine TWPs increased the plant stress. Furthermore, aged TWPs improved soil organic matter (SOM) and total organic carbon (TOC), thereby boosting the microbial enzymes involved in nitrogen cycling. Metabolomic analysis revealed that aged TWPs upregulated key pathways related to carbon and nitrogen metabolism, enhancing plant growth and stress responses. Additionally, rhizosphere bacterial diversity was higher under aged TWPs, favoring nutrient-cycling taxa such as Acidobacteriota and Nitrospirota. Pristine TWPs may lead to overproliferation of certain dominant species, thereby reducing microbial diversity in soil, which could ultimately compromise the soil health. These findings contribute to a deeper understanding of the mechanisms underlying TWP toxicity in plants and highlight the necessity for further research on the impact of aged TWPs across various plant species over different exposure durations for comprehensive risk assessment.

中文翻译：

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原始和老化的轮胎磨损颗粒对 Ipomoea aquatica 和根际微生物群落的影响：来自长期暴露研究的见解


轮胎磨损产生的轮胎磨损颗粒 （TWP） 对环境污染有很大影响。TWP 对生物体的毒性引起了人们的严重关注，但它们对陆生植物的影响仍不清楚。在这里，我们研究了原始和自然老化的 TWP 对空心菜 （Ipomoea aquatica） 及其根际土壤的长期影响。结果表明，自然老化降低了 TWPs 的毒性，土壤和 TWP 本身中多环芳烃 （PAH） 水平的降低证明了这一点。因此，发现老化的 TWP 可促进植物生长和叶绿素含量，而原始 TWP 会增加植物胁迫。此外，老化的 TWP 改善了土壤有机质 （SOM） 和总有机碳 （TOC），从而促进了参与氮循环的微生物酶。代谢组学分析显示，老化的 TWP 上调了与碳和氮代谢相关的关键途径，增强了植物生长和胁迫反应。此外，在老化的 TWP 下，根际细菌多样性较高，有利于营养循环类群，如 Acidobacteriota 和 Nitrospirota。原始的 TWP 可能导致某些优势物种的过度增殖，从而减少土壤中的微生物多样性，最终可能损害土壤健康。这些发现有助于更深入地了解植物中 TWP 毒性的潜在机制，并强调有必要进一步研究不同暴露持续时间内老化的 TWP 对各种植物物种的影响，以进行全面的风险评估。