Journal of Ecology and Rural Environment ›› 2023, Vol. 39 ›› Issue (5): 608-616.doi: 10.19741/j.issn.1673-4831.2022.1122

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Effects of Microplastics on Growth and Physiology of Wheat under Different Temperature and Humidity Conditions

LI Rui-jie1,2,3, TU Chen2,3, YANG Jie2,3, FENG Yu-dong2,3, FAN Qiao-hui1,3, LUO Yong-ming2,3   

  1. 1. Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China;
    2. CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China;
    3. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2022-11-14 Online:2023-05-25 Published:2023-05-24

Abstract: Microplastic pollution, as a global environmental problem, still shows huge challenges in frontier scientific issues. Currently, the research is increasing on the uptake of microplastics by plants, as well as response of plants to microplastics. However, research on environmental factors affecting the uptake of microplastics by plants is still limited. Based on the hydroponic experiment in laboratory, the quantitative uptake of polystyrene (PS) microplastics (0.2 μm) by wheat seedling (Triticum aestivum) was investigated under different temperature and humidity conditions (high transpiration environment: 30 ℃, 55% RH; low transpiration environment: 10 ℃, 85% RH). Furthermore, the changes in wheat growth and the physiological state were also analyzed, including indicators of morphology, photosynthesis and biochemistry. The results show that the accumulation amount of microplastics in wheat increased significantly with the increase of exposure concentration. Besides, the uptake amount of microplastics by wheat roots was 1.5 times higher in high transpiration environment than those in low transpiration environment. Under high transpiration environment, PS microplastics inhibited growth of wheat root and the activity of peroxidase in wheat shoot. Under the condition of high concentration with 200 mg·L-1 of PS microplastics, it showed a significant decrease in the content of chlorophyll b but significant increase in the content of malondialdehyde in wheat roots and activity of superoxide dismutase in wheat shoots. Under low transpiration environment, a high concentration (200 mg·L-1) of PS microplastics caused the content of malondialdehyde significantly increased in wheat shoots. But there were no obvious changes in photosynthesis and the activity of antioxidize in wheat. In conclusion, this study provides powerful evidences that the uptake of microplastics and the corresponding phytotoxic effects on wheat seedling are closely related to the environmental temperature and humidity, as well as the exposure concentration of PS microplastics. The results of this study can provide technical support for the quantitative analysis of uptake and transfer of microplastics by higher plants, and further provide scientific basis for the risk assessment of microplastics in terrestrial ecosystems.

Key words: microplastics, wheat, temperature and humidity, quantitative analysis, photosynthesis, oxidative damage

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