聚苯乙烯纳米塑料(PSNPs)对大豆(Glycine max)种子发芽和幼苗生长的影响

Effects of polystyrene nanoplastics (PSNPs) on seed germination and seedling growth of soybean (Glycine max)

为探讨微塑料对农作物的生态毒理效应,研究了两种粒径(20 nm和100 nm)聚苯乙烯纳米塑料(Polystyrene Nanoplastics, PSNPs)在6个浓度梯度(0、50、100、200、500和1000 mg·L^-1)下对大豆(Glycine max)种子发芽和幼苗生长的影响.结果表明,两种粒径PSNPs均抑制种子发芽能力(发芽势、发芽指数、活力指数、平均发芽速度和发芽率),其中,发芽抑制率在一定程度上与暴露时间呈负相关关系. 20 nm和100 nm PSNPs对根长、芽长和苗长的影响整体呈"低浓度促进,中高浓度抑制"的规律. 20 nm PSNPs对根尖数量无显著影响,而100 nm PSNPs则表现出促进作用. 20 nm和100 nm PSNPs对根直径和干重均有抑制作用.综上, PSNPs的植物毒性与粒径和浓度密切相关,在中等浓度(200 mg·L^-1)时,其对大豆幼苗生长的毒害作用最大.

The influences of polystyrene nanoplastics(PSNPs) with two particle sizes(20 nm and 100 nm) on soybean(Glycine max) seed germination and seedling growth were studied to explore the ecotoxicological effects of microplastics on crops. PSNPs concentrations was designed with 0, 50, 100, 200, 500 and 1000 mg·L^-1. The results showed that PSNPs(20 nm and 100 nm) inhibited the seed germination capacity(germination energy, germination index, vigor index, mean germination speed and germination rate) of Glycine max. Moreover, the germination inhibition rate was negatively correlated to the exposure time to a certain extent. PSNPs(20 nm and 100 nm) promoted the root length, bud length and seedling length of Glycine max treated with low concentration, but suppressed these parameters at medium to high concentration. 20 nm PSNPs had no significant effect on the number of root tips of Glycine max, while 100 nm PSNPs showed a positive effect. PSNPs(20 nm and 100 nm) had a negative impact on the root diameter and dry weight of Glycine max. Overall, the phytotoxicity of PSNPs is closely related to particle size and level. 200 mg·L^-1(intermediate level) PSNPs had the most toxic effect on seedling growth of Glycine max.