LAUSR

The potential risks of micro/nanoplastics on ecological environment, particularly aquatic fauna, have been realized in recent years. However, information about its potential effects on aquatic plants is scarce. In this study, a long-term exposure experiment was conducted to investigate the effects of polystyrene nanoplastics (PS-NPs, 0.16-100 μg/mL) on the early development of an endangered aquatic plant (Ceratopteris pteridoides). Fluorescent images demonstrated that PS-NPs were adsorbed and accumulated on spore surface rapidly and massively with the increase of exposure concentration and time. The adsorption and accumulation of PS-NPs on spore surface posed a negative effect on spore imbibition, causing 2.3-22.4% reduction in final spore size. Spore germination and gametophyte sex differentiation were both negatively affected by PS-NPs exposure, resulting in 10.4-88.0% inhibition in germination ratio and 2.9-53.4% reduction in hermaphroditic gametophyte ratio. Additionally, PS-NPs were observed to penetrate into the roots of gametophytes. Higher concentration of PS-NPs (100 μg/mL) can even induce pathological changes on gametophytes, although with a low incidence (4.9%). The results above indicated that exposure to PS-NPs caused a series of disruption in the early development stages from the stage of imbibition onward, and are likely to pose an eco-physiological risk on the reproductive success of endangered ferns.