Li Yuanfu, Liu Li, Meng Xiaoou, Qiu Jingsi, Liu Yanmei, Zhao Feng, Tan Huihua
Guangxi Key Laboratory for Agro-Environment and Agric-Product Safety, National Demonstration Center for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning, Guangxi 530004, China.
Guangxi Subtropical Crops Research Institute, Nanning, Guangxi 530004, China; Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Nanning, Guangxi 530004, China.
J Hazard Mater. 2025 Jun 15;490:137803. doi: 10.1016/j.jhazmat.2025.137803. Epub 2025 Mar 3.
Microplastics (MPs) are widely distributed in agricultural systems. However, studies on the comprehensive effects of MPs on nitrogen cycling in crop rhizosphere soil, and the changes this effect causes to crop growth is still limited. In this study, we investigated how three types of 5 % MPs (polystyrene, PS; polyethylene, PE; polyvinyl chloride, PVC) affect soybean growth by altering rhizosphere soil nitrogen cycling. These MPs have no direct toxic effects on soybean under hydroponic conditions. However, under soil cultivation conditions, PE and PS promoted soybean growth and increased soybean roots nitrogen content and nitrogen assimilation enzyme activity, while PVC does the opposite. Further study found that PE and PS increased the inorganic nitrogen content, and the activity of nitrogen cycle-related enzymes and the abundance of genes and microorganism in rhizosphere soil. Meanwhile, PVC significantly reduced the inorganic nitrogen contents, inhibited the activity of nitrogen cycling related enzymes, and destroyed the microbial community structure in rhizosphere soil. More importantly, PVC significantly reduced the abundance of nitrogen cycle-related genes and microorganisms, and increased the abundance of viruses. These results indicated that PE and PS promote soybean growth by activating the nitrogen cycle in the rhizosphere soil and increasing the soil nitrogen content, whereas PVC inhibits soybean growth by disrupting the nitrogen cycle in the rhizosphere soil and reducing its nitrogen content.
微塑料（MPs）广泛分布于农业系统中。然而，关于MPs对作物根际土壤氮循环的综合影响以及这种影响对作物生长造成的变化的研究仍然有限。在本研究中，我们调查了三种5%的MPs（聚苯乙烯，PS；聚乙烯，PE；聚氯乙烯，PVC）如何通过改变根际土壤氮循环来影响大豆生长。这些MPs在水培条件下对大豆没有直接毒性作用。然而，在土壤栽培条件下，PE和PS促进了大豆生长，增加了大豆根系氮含量和氮同化酶活性，而PVC则相反。进一步研究发现，PE和PS增加了根际土壤中的无机氮含量、氮循环相关酶的活性以及基因和微生物的丰度。同时，PVC显著降低了无机氮含量，抑制了氮循环相关酶的活性，并破坏了根际土壤中的微生物群落结构。更重要的是，PVC显著降低了氮循环相关基因和微生物的丰度，并增加了病毒的丰度。这些结果表明，PE和PS通过激活根际土壤中的氮循环并增加土壤氮含量来促进大豆生长，而PVC则通过破坏根际土壤中的氮循环并降低其氮含量来抑制大豆生长。
