Department of Botany, School of Biology, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece.
Laboratory of Environmental Research and Education, Democritus University of Thrace, Nea Hili, GR-68100 Alexandroupolis, Greece.
Sci Total Environ. 2020 Jun 1;719:137378. doi: 10.1016/j.scitotenv.2020.137378. Epub 2020 Feb 18.
The ecotoxicity of titanium dioxide nanoparticles (TiO NPs) is of increasing concern due to their extensive use in a variety of applications. This study aims to achieve a better understanding of TiO NP ecotoxicity by assessing for the first time their effects on seagrasses. Changes in leaf cell structure and viability, and leaf elongation in Halophila stipulacea exposed under laboratory conditions to environmentally relevant TiO NP concentrations (0.0015-1.5 mg L) for 8 days were assessed. Actin filament (AF) disturbance firstly occurred in differentiating cells at 0.0015 mg L on the 8th day, while in meristematic cells at 0.15 mg L on the 6th day, both deteriorating concentration- and time-dependently. Endoplasmic reticulum (ER) appeared aggregated firstly at 0.015 mg L on the 8th day and earlier at the highest concentrations, while microtubules and cell ultrastructure appeared unaffected. Dead cells mainly occurred in older leaves; dead tooth, margin and intercostal epidermal cells exceeded 5% at 0.15-1.5 mg L. A significant leaf elongation inhibition occurred at 0.015-1.5 mg L in older leaves and at 1.5 mg L in young apical leaves. AF, ER and leaf elongation impairment in H. stipulacea, being susceptible response parameters, could be used as early warning markers. A risk quotient >1 was calculated, indicating that TiO NPs may pose a significant risk to the environment. The data presented underline the need for additional TiO NP-seagrasses toxicity information, and could be utilized for the protection of the coastal environment.
由于二氧化钛纳米粒子（TiO NPs）在各种应用中的广泛使用，其生态毒性引起了越来越多的关注。本研究旨在通过首次评估其对海草的影响，来更好地了解 TiO NP 的生态毒性。在实验室条件下，将浓度分别为 0.0015-1.5 mg/L 的环境相关 TiO NP 暴露于Halophila stipulacea 叶片 8 天，评估叶片细胞结构和活力变化以及叶片伸长情况。结果表明，分化细胞中肌动蛋白丝（AF）的紊乱最先在第 8 天的 0.0015 mg/L 时发生，而在分生细胞中则在第 6 天的 0.15 mg/L 时发生，且均呈浓度和时间依赖性恶化。内质网（ER）最初在第 8 天的 0.015 mg/L 时聚集，在较高浓度时更早出现，而微管和细胞超微结构不受影响。死亡细胞主要发生在较老的叶片中；在 0.15-1.5 mg/L 时，死亡的齿、边缘和肋间表皮细胞超过 5%。在较老的叶片中，0.015-1.5 mg/L 时叶片伸长受到显著抑制，在幼叶的顶端叶片中 1.5 mg/L 时受到显著抑制。H. stipulacea 中 AF、ER 和叶片伸长受损，作为敏感反应参数，可以作为早期预警标记。计算得出的风险商数>1，表明 TiO NPs 可能对环境构成重大风险。所提供的数据强调了需要更多的 TiO NP-海草毒性信息，并可用于保护沿海环境。
