Wheat (Triticum aestivum L.) seedlings performance mainly affected by soil nitrate nitrogen under the stress of polyvinyl chloride microplastics

Microplastics are exotic pollutants and are increasingly detected in soil, but it remains poorly understood how microplastics impact soil and plant systematically. The present study was conducted to evaluate the effects of polyvinyl chloride microplastics (PVC-MPs) on wheat seedlings performance and soil properties. Under the stress of PVC-MPs, no new substance and functional groups were generated in soil by X-ray diffraction and the fourier transform infrared spectroscopy analyses, whereas the diffraction and characteristic peaks and of soil was affected by PVC-MPs. Wheat seedlings shoot biomass and soil nitrate nitrogen were significantly inhibited by PVC-MPs. Chlorophylls were not significant affected by PVC-MPs. Superoxide dismutase, catalase, and peroxidase activities in wheat seedlings increased, while malondialdehyde and proline contents decreased significantly. Redundancy analysis displayed that wheat seedlings traits can be largely explained by soil nitrate nitrogen. Our results indicate that PVC-MPs have more significant influence on soil structure than on soil substance composition. Moreover, even though antioxidant enzyme activities were improved to respond the stress of PVC-MPs, wheat seedlings are not severely impacted by PVC-MPs. Besides, soil nitrate nitrogen is the main factor on wheat seedlings performance and wheat seedlings are prone to ensure the root growth under the stress of PVC-MPs.