微塑料与铅复合污染对玉米种子萌发与生长的影响

为探明微塑料和重金属复合污染对作物种子萌发与生长的影响，以玉米种子为对象，探究了铅(Pb)和3种微塑料聚乙烯(PE)、聚丙烯(PP)、聚氯乙烯(PVC)]不同单一及复合浓度暴露对玉米种子萌发及其生长的影响.结果表明，Pb单一暴露对玉米种子发芽的抑制总体上随其浓度的升高而增强；与CK相比，500、 1 000和1 500 mg·L^-1PE暴露显著抑制玉米种子发芽，100 mg·L^-1和300 mg·L^-1暴露影响不显著(第5 d除外);所有PP浓度暴露均显著抑制玉米种子发芽；相比PP和PE,PVC单一暴露对玉米发芽抑制较轻.Pb和3种微塑料复合暴露均显著抑制玉米种子发芽，随着时间的增长，抑制逐渐减弱.玉米种子的发芽指数、发芽势和活力指数均随着Pb及3种微塑料单一暴露浓度升高而减小，且在Pb和PE复合暴露下较CK显著减小，但在Pb和PP、 Pb和PVC复合暴露下均无显著变化；3种微塑料中，PVC对玉米种子活力影响相对最轻.10 mg·L^-1Pb和100 mg·L^-1的3种微塑料单...

Effects of Combined Pollution of Microplastics and Lead on Maize Seed Germination and Growth

Microplastics are a new contaminant that are causing worldwide concern. However, an understanding of their impact on agricultural seed germination remains inadequate. To investigate the effects of combined microplastic and heavy metal contamination on crop seed germination and growth, the effects of exposure to different single and combined concentrations of lead (Pb) and three microplasticspolyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC)] on maize seed germination and growth were investigated using maize seeds. The results showed that:the inhibition of maize seed germination by Pb single exposure generally increased with Pb concentration. Compared with that in CK, 500, 1000, and 1500 mg·L^-1 PE exposure significantly inhibited maize seed germination, but 100 and 300 mg·L^-1 exposure had no significant effect (except at d 5). All PP concentration exposures significantly inhibited maize seed germination, with higher concentrations resulting in stronger inhibition. Compared to that under PP and PE exposure, PVC single exposure inhibited maize germination less, and 500, 1000, and 1500 mg·L^-1 exposures produced a facilitative effect at the later stages of germination. The germination index, germination potential, and vigor index of maize seeds decreased with the increase in the single exposure concentration of lead and three types of microplastics, significantly decreased compared with that of CK under the combined exposure of Pb and PE, and did not change significantly under the combined exposure of PP and Pb or PVC and Pb. Among the three types of microplastics, PVC had the least effect on corn seed vigor. Both single exposures of 10 mg·L^-1Pb and 100 mg·L^-1 of the three microplastics promoted maize stalk and root growth, whereas other concentrations showed mostly inhibitory effects. When the PE concentration was 500 mg·L^-1, the 10 and 20 mg·L^-1Pb exposures both promoted maize seed stalk and root growth; however, the combined PP and Pb exposures did not produce significant inhibition, whereas 500 mg·L^-1PVC and 10 mg·L^-1Pb showed the strongest inhibition of maize stalk and root growth under combined PVC and Pb exposures. The effects of combined exposure to microplastics and Pb on the germination and growth of maize seeds were essentially antagonistic, thus slowing down the toxic effects of their respective single exposures on maize seeds.