College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, People's Republic of China.
College of Overseas Education, Nanjing Tech University, Nanjing, Jiangsu Province, 211816, People's Republic of China.
Environ Pollut. 2019 Apr;247:108-117. doi: 10.1016/j.envpol.2019.01.046. Epub 2019 Jan 14.
Polycyclic aromatic hydrocarbons and zinc oxide nanoparticles are ubiquitous pollutants in the environment. However, little information is available about their toxicity interaction in food crops. In this study, seed germination and hydroponic experiments were conducted to assess the impact of ZnO (NPs and bulk at 250, 500 and 1000 mg L) individual and combined with phenanthrene (1 mg L) on wheat growth for 15 days. Under ZnO (NPs and bulk) alone and combined with phenanthrene exposure, dose-dependent toxicity in some indexes (germination rate, biomass, shoot height, root length) was observed. Both ZnO NPs and bulk inhibited plant growth at high concentrations, but no significant difference was observed between them (P > 0.05). The chlorophyll concentration of wheat leaves decreased by 0.43-0.60 fold when the levels of ZnO NPs and bulk treated were elevated. There was a negative correlation between ZnO (NPs and bulk) and total chlorophyll. Hill reaction activity also exhibited the same tendency. Through transmission electron microscopy, ZnO NPs were found in wheat seedling root apoplast and symplasm at 1000 mg L with or without phenanthrene. High doses (500 and 1000 mg L) of ZnO (NPs and bulk) caused more DNA damage to wheat seedling root cells, and ZnO NPs induced stronger genotoxicity than bulk ones to wheat root cells. Superoxide dismutase (SOD) and catalase (CAT) activities of wheat seedling roots decreased at 1000 mg L ZnO (NPs and bulk), especially in the co-exposure treatments. Hence, ZnO (NPs and bulk) combined with phenanthrene cause more damage to wheat seedling roots, and even destroy the antioxidant system. Our findings are helpful for not only assessing the individual and combined toxicity between phenanthrene and ZnO (NPs and bulk), but also for understanding the different response of plants to individual and combined pollution.
多环芳烃和氧化锌纳米颗粒是环境中普遍存在的污染物。然而，关于它们在粮食作物中的毒性相互作用的信息却很少。在这项研究中，进行了种子萌发和水培实验，以评估 ZnO（纳米颗粒和体相，分别为 250、500 和 1000mg/L）单独以及与菲（1mg/L）联合暴露对小麦生长 15 天的影响。在 ZnO（纳米颗粒和体相）单独以及与菲联合暴露下，在某些指标（发芽率、生物量、茎高、根长）中观察到剂量依赖性毒性。高浓度的 ZnO 纳米颗粒和体相均抑制植物生长，但它们之间没有显著差异（P>0.05）。当 ZnO 纳米颗粒和体相处理水平升高时，小麦叶片的叶绿素浓度降低了 0.43-0.60 倍。ZnO（纳米颗粒和体相）与总叶绿素之间存在负相关。希尔反应活性也表现出相同的趋势。通过透射电子显微镜，在有或没有菲的情况下，在 1000mg/L 时发现 ZnO 纳米颗粒存在于小麦幼苗根质外体和共质体中。高剂量（500 和 1000mg/L）的 ZnO（纳米颗粒和体相）对小麦幼苗根细胞造成更大的 DNA 损伤，并且 ZnO 纳米颗粒对小麦根细胞的遗传毒性比体相更强。在 1000mg/L ZnO（纳米颗粒和体相）下，小麦幼苗根中的超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性降低，尤其是在联合暴露处理中。因此，ZnO（纳米颗粒和体相）与菲联合暴露对小麦幼苗根造成更大的损害，甚至破坏抗氧化系统。我们的研究结果不仅有助于评估菲和 ZnO（纳米颗粒和体相）之间的单独和联合毒性，还有助于理解植物对单独和联合污染的不同反应。
