沉水植物对微塑料和抗生素的生理代谢响应机制

Physiological and Metabolic Response of Submerged Plants to Microplastics and Antibiotics

研究微塑料与抗生素对沉水植物的生态影响,为淡水系统生态效应的风险评估提供理论支持和依据。通过模拟试验,研究实验室环境下聚四氟乙烯微粉(PTFE-MPs,平均粒径5μm,浓度50 mg/L),诺氟沙星(NFX,5 mg/L),以及两者联合处理(50 mg/L+5 mg/L)下沉水植物水蕴草的生理响应机制。结果显示,PTFE-MPs和NFX会诱导植物抗逆酶活性和光合作用的调节,并导致植物脂质过氧化,但对植物可溶性糖含量无显著影响;通过非靶向代谢组学检测比较了各处理组的代谢物变化和富集,结果表明各对比组有显著的差异代谢物变化以及代谢通路富集。从研究结果推测植物通过卵磷脂等脂类代谢物以及琥珀酸等氨基酸代谢物水平的调节对其他代谢途径以及生理生化途径进行调控,从而影响植物的生长,增强逆境适应能力。

Accumulation of two emerging pollutants,microplastics(MPs)and antibiotics(Ats),in the aquatic environment has attracted extensive scholarly attention and poses an international ecological challenge.Several studies have demonstrated the individual ecological effects of microplastics and antibi-otics in aquatic ecosystems,but little is known about their combined effects,particularly their combined effects on aquatic plants.In a controlled laboratory environment,we investigated the physiological responses of Elodea densa(Planch.)Casp.when exposed to polytetrafluoroethylene micropowders(PTFE-MPs,average particle size 5µm,concentration 50 mg/L),norfloxacin(NFX,5 mg/L),and the two in combination(50 mg/L+5 mg/L).The physiological and biochemical response mechanisms of E.densa to stress were also investigated.The aim of the study was to provide the data and theory necessary to assess the risks posed by microplastics and antibiotics on freshwater systems.Four treatments were set,including a control group(CK)and three treatment groups:50 mg/L PTFE-MPs(P),5 mg/L NFX(N),and 50 mg/L PTFE-MPs plus 5 mg/L NFX(NP).Exposure duration was 3 weeks and each treatment was run in triplicate.Results show that PTFE-MPs and NFX induced plant stress-resisting enzyme activity and photosynthesis,and led to lipid peroxidation,but had no significant effect on plant soluble sugar content.We also compared metabolite changes and enrichment among the treatments using a non-targeted metabo-lomics assay.Assay results indicate significant changes in metabolites as well as metabolite enrichment among the treatment groups.Based on these results,we hypothesized that plants activate additional metabolic pathways and physiological and biochemical pathways by adjusting the levels of lipid metabo-lites,such as lecithin,and amino acid metabolites,such as succinic acid,thereby affecting plant growth and enhancing adaptation to adverse conditions.In general,the effect of PTFE-MPs on E.densa.was manifested primarily as physiological effects,while NFX exhibited significant biotoxicity.Furthermore,PTFE-MPs and NFX in combination appear to act synergistically,exacerbating the toxic effect of NFX on E.densa.