The effects of microplastics on crop plants have attracted growing attention. However, little is known about the effects of microplastics and their extracts on the growth and physiology of wheat seedlings. In this study, hyperspectral-enhanced dark field microscopy and scanning electron microscopy were used to accurately track the accumulation of 200 nm label-free polystyrene microplastics (PS) in wheat seedlings. The PS accumulated along the root xylem cell wall and in the xylem vessel member and then moved toward to the shoots. In addition, lower concentration (≤ 5 mg·L⁻¹) of microplastics increased root hydraulic conductivity by 80.6 %− 117.0 %. While higher PS treatment (200 mg·L⁻¹) considerably decreased plant pigments content (chlorophyll a, b, and total chlorophyll) by 14.8 %, 19.9 %, and 17.2 %, respectively, and decreased root hydraulic conductivity by 50.7 %. Similarly, catalase activity was reduced by 17.7 % in root and 36.8 % in shoot. However, extracts from the PS solution showed no physiological effect on wheat. The result confirmed that it was the plastic particle, rather than the chemical reagents added in the microplastics, contributed to the physiological variation. These data will benefit to better understanding on the behavior of microplastics in soil plants, and to providing of convincing evidence for the effects of terrestrial microplastics.

微塑料对农作物的影响越来越受到关注。然而，关于微塑料及其提取物对小麦幼苗生长和生理的影响知之甚少。在这项研究中，高光谱增强暗场显微镜和扫描电子显微镜被用来准确追踪 200 nm 无标记聚苯乙烯微塑料 (PS) 在小麦幼苗中的积累。PS 沿根木质部细胞壁和木质部导管成员积累，然后向枝条移动。此外，较低浓度（≤ 5 mg·L ^-1）的微塑料使根系水力传导率增加了80.6 %− 117.0 %。而较高的PS处理(200 mg·L ⁻¹) 显着降低了植物色素含量（叶绿素 a、b 和总叶绿素），分别降低了 14.8%、19.9% 和 17.2%，根系水力传导率降低了 50.7%。同样，过氧化氢酶活性在根中降低了 17.7%，在芽中降低了 36.8%。然而，PS 溶液的提取物对小麦没有生理影响。结果证实，造成生理变化的是塑料颗粒，而不是微塑料中添加的化学试剂。这些数据将有助于更好地了解微塑料在土壤植物中的行为，并为陆地微塑料的影响提供令人信服的证据。