微塑料污染已经成为全世界关注的问题，当微塑料与土壤系统中的重金属等其他污染物相互作用时，微塑料会对植物的生长发育产生不利影响，但微塑料和重金属之间的相互作用对植物造成的影响研究较少。研究以玉米种子为研究对象，探究不同粒径（50 μm和100 μm）聚丙烯微塑料（PP-MPs）和重金属镉（Cd）共同暴露条件下对玉米种子萌发、幼苗生长以及氧化胁迫的影响。结果表明：PP-MPs+Cd处理种子的发芽率、发芽势和活力指数都有所提高，Cd处理和PP-MPs处理对平均发芽时间（MGT）均有抑制作用，Cd、50 μm PP-MPs+Cd和100 μm PP-MPs+Cd三个处理对MGT均有不同程度上的抑制作用。Cd和100 μm PP-MPs+Cd处理在第3天和第7天都抑制了玉米幼苗根和芽的生长；第3天Cd处理和100 μm PP-MPs+Cd处理的鲜重和干重分别下降8.32%、17.31%和9.91%、17.86%；从结果总体来看，PP-MPs+Cd处理对玉米根和芽的过氧化氢酶（CAT）和过氧化物酶（POD）活性有促进作用，但100 μm PP-MPs+Cd处理POD活性下降了2.82%。研究为微塑料和重金属对玉米及其他作物生长产生的毒效作用提供了依据。

Microplastic pollution has become a concern around the world, when microplastics interact with other pollutants such as heavy metals in the soil system, microplastics will adversely affect the growth and development of plants, but the interaction between microplastics and heavy metals on plants is less studied. In this study maize seeds were used as the research object to explore the effects of polypropylene microplastics(PP-MPs) and heavy metal cadmium (Cd) on seed germination, seedling growth and oxidative stress of maize with different particle sizes (50 μm and 100 μm). The results showed that the germination rate, germination potential and viability index of PP-MPs+Cd treated seeds were improved, Cd treatment and PP-MPs treatment had inhibitory effects on the mean germination time (MGT), and Cd, 50 μm PP-MPs+Cd and 100 μm PP-MPs+Cd treatments all had certain inhibitory effects on MGT to varying degrees. Cd and 100 μm PP-MPs+Cd treatment inhibited the growth of maize seeding roots and shoots on both the third and the seventh days. On the third day, the fresh weight and dry weight of Cd treatment and 100 μm PP-MPs+Cd treatment decreased by 8.32%, 17.31%, 9.91% and 17.86%, respectively. Overall, PP-MPs+Cd treatment promoted catalase (CAT) and peroxidase (POD) activities in maize roots and shoots, but POD activity decreased by 2.82% at 100 μm PP-MPs+Cd treatment. This study provides a basis for the toxic effects of microplastics and heavy metals on the growth of maize and other crops.