Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh-202002, UP, India.
Metallomics. 2018 Sep 19;10(9):1315-1327. doi: 10.1039/c8mt00093j.
There has been rapid increase globally in the production of functionally divergent nanoparticles in recent times. The uncontrolled discharge of such nanomaterials is a serious threat to the environment. We assess the impact of various-sized metal oxide nanoparticles (MONPs) on cell cycle progression and induction of oxidative stress in onions. Of these, CuO-NPs and TiO2-NPs significantly reduced the mitotic index (MI) by 28% and 17%, respectively, whereas Al2O3-NPs augmented the MI by 13% compared to untreated onion roots. The NPs internalization into the root tissues followed a dose dependent fashion. Also, several types of chromosomal aberration such as bridges, stickiness, vagrant, broken, and lag chromosomes were noticed. The reactive oxygen species activity of roots growing under CuO-NPs, Al2O3-NPs, and TiO2-NPs was significantly increased by 58, 30, and 10%, respectively. The superoxide dismutases activity (U g-1 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, catalase activity (mmoles min-1 g-1 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 nitroblue tetrazolium showed a dose dependent increase in roots treated with Al2O3-NPs and TiO2-NPs. Interestingly, under CuO-NPs exposure, the absorbance was considerably high at 200 μg ml-1 which dropped at 2000 μg ml-1 suggesting a clear attenuation of O2˙- by superoxide scavenging enzymes. The present findings provide base line data for better understanding of the mechanistic basis of phytotoxicity of MONPs to onion plants which can further be extended to other vegetable crops.
近年来，全球范围内功能性差异纳米颗粒的产量迅速增加。这些纳米材料的不受控制的排放对环境构成了严重威胁。我们评估了各种尺寸的金属氧化物纳米颗粒（MONPs）对洋葱细胞周期进程和氧化应激诱导的影响。其中，CuO-NPs 和 TiO2-NPs 分别使有丝分裂指数（MI）降低了 28%和 17%，而 Al2O3-NPs 使 MI 增加了 13%，与未处理的洋葱根相比。纳米颗粒进入根组织的内化遵循剂量依赖的方式。此外，还观察到几种类型的染色体畸变，如桥、粘性、流浪、断裂和滞后染色体。在 CuO-NPs、Al2O3-NPs 和 TiO2-NPs 下生长的根的活性氧物种活性分别显著增加了 58%、30%和 10%。根的超氧化物歧化酶活性（U g-1 FW）从 2.4 ± 0.4（对照）增加到 6.1 ± 0.8（CuO-NPs）、4.1 ± 0.2（Al2O3-NPs）和 2.9 ± 0.2（TiO2-NPs），而过氧化氢酶活性（mmoles min-1 g-1 FW）记录为 18.5 ± 2.1（CuO-NPs）、15 ± 1.1（Al2O3-NPs）和 13.8 ± 1（TiO2-NPs），而 11.4 ± 1（对照）。由于超氧化物（O2˙-）与硝基蓝四唑反应形成的甲臜显示出与 Al2O3-NPs 和 TiO2-NPs 处理的根的剂量依赖性增加。有趣的是，在 CuO-NPs 暴露下，在 200 μg ml-1 时吸收相当高，在 2000 μg ml-1 时下降，表明超氧化物清除酶对 O2˙-的清除明显减弱。本研究结果为更好地理解 MONPs 对洋葱植物的植物毒性的机制基础提供了基准数据，这可以进一步扩展到其他蔬菜作物。
