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Chromosomal aberrations, cell suppression and oxidative stress generation induced by metal oxide nanoparticles (MONPs) in onion (Allium cepa) bulb

Abstract

Globally, there has been rapid increase in the production of functionally divergent nanoparticles in recent times. The uncontrolled discharge of such nanomaterials on the other hand is a serious threat to the sustainability of environment. Considering these, the impact of varying sized metal oxide nanoparticles on cell cycle progression and induction of oxidative stress in onion was assessed. Of these, CuO-NPs and TiO2-NPs significantly reduced the mitotic index (MI) by 28% and 17% whereas Al2O3-NPs augmented MI by 13% compared to untreated onion roots. The NPs internalized into the root tissues followed a dose dependent fashion. Also, several types of chromosomal aberrations such as bridges, stickiness, vagrant, broken, and lag chromosomes were noticed. The ROS activity of roots growing under CuO-NPs, Al2O3-NPs, and TiO2-NPs was significantly increased by 58, 30, and 10%, respectively. The SOD activity (U/g FW) of roots increased from 2.4±0.4 (control) to 6.1±0.8 (CuO-NPs), 4.1±0.2 (Al2O3-NPs) and 2.9±0.2 (TiO2-NPs) whereas, CAT activity (mmoles/min/g FW) was recorded as 18.5±2.1 (CuO-NPs), 15±1.1 (Al2O3-NPs) and 13.8±1 (TiO2-NPs) against 11.4±1 (control). The formazan formed due to superoxide (O2●‾) reaction with NBT showed a dose dependent increase in roots treated with Al2O3-NPs and TiO2-NPs. Interestingly, under CuO-NPs exposure, the absorbance was considerably highest at 200 µg/ml which dropped at 2000 µg/ml suggesting a clear attenuation of O2●‾ by superoxide scavenging enzymes. The present findings provides a base line data for better understanding the mechanistic basis of phyto-toxicity of MONPs to onion plants which can further be extended to other vegetable crops.

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Supplementary files

Publication details

The article was received on 24 Apr 2018, accepted on 02 Aug 2018 and first published on 06 Aug 2018


Article type: Paper
DOI: 10.1039/C8MT00093J
Citation: Metallomics, 2018, Accepted Manuscript
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    Chromosomal aberrations, cell suppression and oxidative stress generation induced by metal oxide nanoparticles (MONPs) in onion (Allium cepa) bulb

    B. Ahmed, M. Shahid, M. S. Khan and J. Musarrat, Metallomics, 2018, Accepted Manuscript , DOI: 10.1039/C8MT00093J

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