环境浓度下的纳米塑料对假微型海链藻的影响

he Effects of Nanoplastics with Environmentally Relevant Concentrations on Thalassiosira pseudonana

为了解环境浓度海洋纳米塑料(Nanoplastics, NPs)对微藻的影响,本研究以两种粒径(0.1和1μm)的聚苯乙烯纳米塑料(Polystyrene nanoplastics, PSNPs)和海洋模式硅藻假微型海链藻(Thalassiosira pseudonana)为研究对象,从种群、光合生理、细胞色素、胞外聚合物(Extracelluar polymeric substances, EPS)和转录水平上比较环境浓度(5μg·L-1)下两种粒径NPs对假微型海链藻的影响。研究结果表明:(1)假微型海链藻经环境浓度下的两种粒径(0.1和1μm)的NPs处理后,前48 h内其生长和细胞色素组成均没有显著变化,但光合生理指标中的非光化学淬灭(Non-photochemical quenching, NPQ)显著上升。(2)假微型海链藻经环境浓度下的NPs处理后,其产生的EPS总量下降,但蛋白/碳水化合物上升,疏水性变强。(3)环境浓度下的NPs能够引起假微型海链藻的基因(LHCX、GPI、ABCt、APX、NRT等)表达的变化,0.1μm NPs胁迫下的差异表达基因比1μm NPs胁迫下的更多,差异表达量更显著。综合分析得到结论:环境浓度下的NPs能够对假微型海链藻产生影响,0.1μm NPs产生的影响更大。

To investigate the effects of environmental concentrations of nano-plastics(NPs)on marine microalgae,we chose two kinds of(0.1 and 1μm)polystyrene(PS)NPs and marine modelling diatom Thalassiosira pseudonana as research target,and studied the environmentally relevant concentrations(5μg·L-1)of the two kinds of NPs on T.pseudonana in the aspects of the population,photosynthetic physiology,cellular pigments,extracellular polymeric substances(EPS)and transcriptomic levels.The results showed:(1)There were no significant changes in the population growth and cellular pigments of T.pseudonana,but the photosynthetic parameters regarding to Non-Photochemical Quenching(NPQ)values showed certain changes at 48 h.(2)The total EPS contents produced by T.pseudonana decreased in the NPs treatments,while the protein/carbohydrates ratios increased,leading to higher hydrophobicity of EPS.(3)NPs of environmentally relevant concentrations caused gene(LHCX,GPI,ABCt,APX,NRT)expression changes in T.pseudonana,where more gene changes and more significantly differential expressions were found under 0.1 than in 1μm NPs exposure.Therefore,we concluded that the environmental relevant concentration of NPs caused physiological responses of T.pseudonana,and the effects of 0.1μm NPs were more obvious than 1μm NPs.