The development of agricultural technologies has intensified the use of plastic in this sector. Products of plastic degradation, such as microplastics (MPs), potentially threaten living organisms, biodiversity and agricultural ecosystem functioning. Thus, biodegradable plastic materials have been introduced to agriculture. However, the effects of biodegradable plastic substitutes on soil ecosystems are even less known than those of traditional ones. Here, we studied the effects of environmentally relevant concentrations of MPs prepared from a biodegradable plastic (a starch-polybutylene adipate terephthalate blend, PBAT-BD-MPs) on the growth and defense mechanisms of lettuce (Lactuca sativa) in CLIMECS system (CLImatic Manipulation of ECosystem Samples). PBAT-BD-MPs in the highest concentrations negatively affected some traits of growth, i.e., dry weight percentage, specific leaf area, and both C and N contents. We observed more profound changes in plant physiology and biochemistry, as PBAT-BD-MPs decreased chlorophyll content and triggered a concerted response of plant defense mechanisms against oxidative stress. In conclusion, exposure to PBAT-BD-MPs induced plant oxidative stress and activated plant defense mechanisms, leading to oxidative homeostasis that sustained plant growth and functioning. Our study highlights the need for in-depth understanding of the effect of bioplastics on plants.

中文翻译：

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可生物降解的微塑料会引起生菜 （Lactuca sativa） 防御机制的深刻变化，并在一定程度上恶化生长特性


农业技术的发展加强了塑料在该领域的使用。塑料降解产物，如微塑料 （MP），可能威胁到生物体、生物多样性和农业生态系统的功能。因此，可生物降解的塑料材料已被引入农业。然而，可生物降解塑料替代品对土壤生态系统的影响甚至比传统塑料替代品更不为人知。在这里，我们研究了由可生物降解塑料（淀粉-聚己二酸对苯二酸丁二醇酯混合物，PBAT-BD-MPs）制备的 MPS 的环境相关浓度对生菜 （Lactuca sativa） 在 CLIMECS 系统中生长和防御机制的影响（ECosystem 样品的气候操作）。最高浓度的 PBAT-BD-MPs 对一些生长性状产生负面影响，即干重百分比、比叶面积以及 C 和 N 含量。我们观察到植物生理学和生物化学发生了更深刻的变化，因为 PBAT-BD-MPs 降低了叶绿素含量并触发了植物防御机制对氧化应激的协同反应。总之，暴露于 PBAT-BD-MPs 诱导植物氧化应激并激活植物防御机制，导致维持植物生长和功能的氧化稳态。我们的研究强调了深入了解生物塑料对植物影响的必要性。