Emerging contaminants such as microplastics and engineered nanoparticles (NPs) have become an environmental issue of global concern, but little is known about their joint effects in soil–plant systems. We studied the effects of two microplastics, conventional non-degradable high–density polyethylene (HDPE) and biodegradable polylactic acid (PLA), on maize growth and arbuscular mycorrhizal (AM) fungal communities in a soil spiked with or without ZnO NPs. HDPE and low–dose PLA promoted plant growth, while high–dose PLA significantly decreased maize shoot (by 16%–40%) and root biomass (by 28%–50%), indicating high-dose PLA may have strong phytotoxicity. ZnO NPs displayed non-significant effects on plant growth, but caused greater Zn accumulation in plants. Both HDPE and PLA further increased Zn concentrations in roots, while decreasing Zn translocation to aerial parts. High–throughput sequencing showed that microplastics and ZnO NPs singly and jointly influenced AM fungal community composition and diversity, particularly the relative abundance of dominant genera. The presence of ZnO NPs and microplastics generally increased soil pH. Overall, our findings imply increasing contamination by microplastics and NPs can have profound ecological impacts on plant fitness, plant quality, and soil microbial community composition and diversity, resulting in uncertain consequences for agroecosystems.

诸如塑料微粒和工程纳米颗粒（NPs）之类的新兴污染物已成为全球关注的环境问题，但人们对其在土壤-植物系统中的共同作用知之甚少。我们研究了两种微塑料，传统的不可降解的高密度聚乙烯（HDPE）和可生物降解的聚乳酸（PLA），在加或不加ZnO NP的土壤中对玉米生长和丛枝菌根（AM）真菌群落的影响。HDPE和低剂量的PLA促进了植物的生长，而高剂量的PLA则显着降低了玉米芽（降低了16％–40％）和根系生物量（降低了28％–50％），表明高剂量的PLA可能具有很强的植物毒性。ZnO NPs对植物的生长没有显着影响，但会导致植物中更多的Zn积累。HDPE和PLA都进一步增加了根中的锌含量，同时减少锌向空中部分的转运。高通量测序表明，微塑料和ZnO NP单独和共同影响AM真菌的群落组成和多样性，尤其是优势属的相对丰度。ZnO NP和微塑料的存在通常会提高土壤pH值。总体而言，我们的发现表明，微塑料和NP污染的增加可能对植物适应性，植物质量以及土壤微生物群落组成和多样性产生深远的生态影响，从而给农业生态系统带来不确定的后果。ZnO NP和微塑料的存在通常会提高土壤pH值。总体而言，我们的发现表明，微塑料和NP污染的增加可能对植物适应性，植物质量以及土壤微生物群落组成和多样性产生深远的生态影响，从而给农业生态系统带来不确定的后果。ZnO NP和微塑料的存在通常会提高土壤pH值。总体而言，我们的发现表明，微塑料和NP污染的增加可能对植物适应性，植物质量以及土壤微生物群落组成和多样性产生深远的生态影响，从而给农业生态系统带来不确定的后果。