Mitochondrial and Chromosomal Damage Induced by Oxidative Stress in Zn2+ Ions, ZnO-Bulk and ZnO-NPs treated Allium cepa roots

摘要

Large-scale synthesis and release of nanomaterials in environment is a growing concern for human health and ecosystem. Therefore, we have investigated the cytotoxic and genotoxic potential of zinc oxide nanoparticles (ZnO-NPs), zinc oxide bulk (ZnO-Bulk), and zinc ions (Zn2+) in treated roots of Allium cepa, under hydroponic conditions. ZnO-NPs were characterized by UV-visible, XRD, FT-IR spectroscopy and TEM analyses. Bulbs of A. cepa exposed to ZnO-NPs (25.5?nm) for 12?h exhibited significant decrease (23?±?8.7%) in % mitotic index and increase in chromosomal aberrations (18?±?7.6%), in a dose-dependent manner. Transmission electron microcopy and FT-IR data suggested surface attachment, internalization and biomolecular intervention of ZnO-NPs in root cells, respectively. The levels of TBARS and antioxidant enzymes were found to be significantly greater in treated root cells vis-à-vis untreated control. Furthermore, dose-dependent increase in ROS production and alterations in ΔΨmPO2? at 1240?cm?1 and stretching of C-O ribose at 1060?cm?1, suggestive of nuclear damage. Overall, the results elucidated A. cepa, as a good model for assessment of cytotoxicity and oxidative DNA damage with ZnO-NPs and Zn2+ in plants.