Impact of nano-CuO stress on rice (Oryza sativa L.) seedlings

• Published in: Chemosphere (Oxford) Vol. 93; no. 6; pp. 906 - 915
• Main Authors: Shaw, Arun Kumar, Hossain, Zahed
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2013; Elsevier
• Subjects: anthropogenic activities; Antioxidant; Biological and medical sciences; carotenoids; copper; Copper - toxicity; Fundamental and applied biological sciences. Psychology; growth performance; hydrogen peroxide; Hydrogen Peroxide - metabolism; leaves; Nano-CuO stress; Nanoparticles; Nanoparticles - toxicity; Nanotoxicology; Non agrochemicals pollutants; Oryza - drug effects; Oryza - growth & development; Oryza - metabolism; Oryza sativa; Oxidative Stress; particle size; Phytopathology. Animal pests. Plant and forest protection; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; proline; Proline - metabolism; Rice; roots; ROS; seed germination; seedling growth; seedlings; Seedlings - drug effects; Seedlings - growth & development; Seedlings - metabolism; Soil Pollutants - toxicity; toxicity; viability; NPs; Nanoparticles; GSSG; NBT; Nano-CuO stress; DAB; Nanotoxicology; ROS; MDA; Antioxidant; GSH; Rice; Oxidative stress; Monocotyledones; Reactive oxygen species; Nanoparticle; Toxicity; Plant juvenile growth stage; Cereal crop; Copper Oxides; Oryza sativa; Phytotoxicity; Enzymatic activity; Gramineae; Angiospermae; Spermatophyta; Nanostructured materials; oxidized glutathione; nitro blue tetrazolium; reduced glutathione; reactive oxygen species; malondialdehyde; 3′3′-diaminobenzidine
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2013.05.044

•The present study highlights the response of rice seedlings to nano-CuO stress.•Stress induced modulation of antioxidant enzymes and metabolites were studied.•Histochemical staining with NBT and DAB indicate severe oxidative burst.•Elevated APX and GR activity do not protect stressed cells from oxidative damage.•Decline in DHAR renders stressed cells in futile recycling of ascorbate pool. Indiscriminate release of metal oxide nanoparticles (NPs) into the environment due to anthropogenic activities has become a serious threat to the ecological system including plants. The present study assesses the toxicity of nano-CuO on rice (Oryza sativa cv. Swarna) seedlings. Three different levels of stress (0.5mM, 1.0mM and 1.5mM suspensions of copper II oxide, <50nm particle size) were imposed and seedling growth performance was studied along control at 7 and 14d of experiment. Modulation of ascorbate–glutathione cycle, membrane damage, in vivo ROS detection, foliar H2O2 and proline accumulation under nano-CuO stress were investigated in detail to get an overview of nano-stress response of rice. Seed germination percentage was significantly reduced under stress. Higher uptake of Evans blue by nano-CuO stressed roots over control indicates loss of root cells viability. Presence of dark blue and deep brown spots on leaves evident after histochemical staining with NBT and DAB respectively indicate severe oxidative burst under nano-copper stress. APX activity was found to be significantly increased in 1.0 and 1.5mM CuO treatments. Nevertheless, elevated APX activity might be insufficient to scavenge all H2O2 produced in excess under nano-CuO stress. That may be the reason why stressed leaves accumulated significantly higher H2O2 instead of having enhanced APX activity. In addition, increased GR activity coupled with isolated increase in GSH/GSSG ratio does not seem to prevent cells from oxidative damages, as evident from higher MDA level in leaves of nano-CuO stressed seedlings over control. Enhanced proline accumulation also does not give much protection against nano-CuO stress. Decline in carotenoids level might be another determining factor of meager performance of rice seedlings in combating nano-CuO stress induced oxidative damages.