In this study,the morphological characteristics,specific surface area,pore size,particle size,contact angle,and Fourier transform infrared spectroscopy of polyethylene microplastics(PE-MPs)before and after aging were measured to analyze the changes of their physicochemical properties.Chinese cabbage seeds were used as test organisms to explore the effects of PE-MPs on tetracycline(TC)phytotoxicity through early plant growth experiments.Results showed that the particles of PE-MPs broke and became smaller after aging;the particle size(Dx50)decreased from 91.4 μm to 77.3 μm,while the specific surface area increased from 4.150 8 m2·g-1to 4.967 1 m2·g-1.The contact angle decreased from 103° to 79°,indicating a change from hydrophobicity to hydrophilicity.The number of oxygen-containing functional groups increased,and a new absorption band of carbonyl(C=O)was found at 1 650-1 800 cm-1.Compared with TC alone,0.5 mg·L-1 and 5 mg·L-1 TC had no significant effect on the germination of Chinese cabbage seeds in the presence of PE-MPs before and after aging;however,the inhibitory effects on the elongation of radicles and the synthesis of photosynthetic pigments in cotyledons intensified with the increase of PE-MPs content.Among them,the maximum reduction in relative radicle length was 18.9 percentage points,and the maximum reduction in the relative content of photosynthetic pigments was 51.1 percentage points.Compared with PE-MPs before aging,the exacerbation effect of PE-MPs on TC phytotoxicity weakens after aging.
关键词
聚乙烯微塑料/四环素/老化/亲疏水性/植物毒性/子叶光合色素
Key words
polyethylene microplastics/tetracycline/aging/hydrophilicity-hydrophobicity/phytotoxicity/photosynthetic pigments in cotyledons
维普
万方数据