The Effect of Microplastics with Different Types, Particle Sizes, and Concentrations on the Germination of Non-Heading Chinese Cabbage Seed

Microplastics (MPs) are a new type of pollutant widely distributed in the environment. The ecological risks caused by MPs are becoming increasingly serious, especially in cultivated land where pollution is more likely to accumulate. In this paper, the effects of different types, particle sizes, and concentrations of MPs on the seed germination of non-heading Chinese cabbage were analyzed to reveal their potential mechanisms. Five types of MPs, polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polystyrene (PS), were used for correlation analysis. The results showed that the effect of PVC and PET on seed germination was greater than that of PP, PS, and PE. PVC and PP promoted the growth of germinated seeds, while PET and PS showed a certain degree of inhibition. The effect of MPs with a particle size of 6.5–150 μm on seed germination was obvious. Low-concentration MPs (<1 g/L) had a weak inhibitory effect on seed germination. When the concentration was 1 g/L, 75 μm-PP, 75 μm-PVC, and 150 μm-PS promoted the growth of germinated seeds, while 48 μm PET showed inhibition. At high concentration, PP and PS inhibited amylase activity. In general, MPs’ effects showed significant differences according to different types, particle sizes, and concentrations.