Phytotoxic Assessment of Nickel Oxide (NiO) Nanoparticles in Radish

Abstract

Nanomaterials are rapidly being used in manufacturing products in our daily life such as biosensors, cosmetics, food packaging, medicines, etc., and these products are coming in the global market approximately at the rate of 3–4 per week. Despite manifold benefits of the power of nanomaterials, there are open questions about how the small-sized materials affect the environment and human health, while very few reports are available on the hazards of nanoparticles. In the present study, we examined the effect of NiO nanoparticles in inducing toxicity, lipid peroxidation and membrane damage, ROS generation, and antioxidant activities. It has been observed that the radish seeds treated with NiO nanoparticles (0.25, 0.5, 1.0, 1.5, and 2.0 mg mL−1) for 4 h had significant effect on seed germination and root growth. Uptake and translocation of NiO nanoparticles into the cytoplasm were confirmed by transmission electron microscopy (TEM), which showed mitochondrial fission, abundance of peroxisomes, and excessive vacuolization. Generation of ROS and membrane damage were qualitatively assessed by the DCF and Rh123 staining. Roots treated with NiO nanoparticles showed remarkable reduction in fluorescence in comparison to control. Concentration-dependent changes in activity of antioxidant enzymes, viz., glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and lipid peroxidation (LPO), were also observed. The data generated by the treatments of NiO nanoparticles in radish will provide a strong background to draw attention on environmental hazards of nanomaterials.