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International Conference on

Recent Trends in Environmental Sustainability

ESCON22/ETERM/12
Effects of zinc oxide nanoparticles on antioxidants, chlorophyll contents, and proline in
Persicaria hydropiper L. and its potential for Pb phytoremediation

2
*1
Fazal Hussain , Fazal Hadi 1,2 , Qiu Rongliang
1 Department of Biotechnology, University of Malakand, KP, Chakdara 18800, Pakistan
2 School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou
510275, China
Correspondence: fazalhussain70@gmail.com

Abstract
Applications of nanoparticles and plants for efficient restoration of heavy metal-polluted water
and soil are an emerging approach and need to be explored. Hydroponic study was performed
to find the role of zinc oxide nanoparticles (ZnO NPs) in plant growth, antioxidative response,
and lead (Pb) accumulation in Persicaria hydropiper L. Seedlings were grown in Pb-polluted
media amended with 5, 10, 15, and 20 mg L−1 ZnO NPs. Inductively coupled plasma
spectroscopy (ICP) was used for Pb analysis in plant tissues. Pb significantly inhibited seedling
growth, and ZnO NPs alleviated Pb-induced stress by promoting plant growth, improved
chlorophyll and carotenoid contents. Oxidative stress was ameliorated in ZnO NPs exposed
seedlings through enhanced production of free proline, phenolics, flavonoids and activation of
antioxidative enzymes. Pb accumulation boosted in ZnO NP treatments, and highly significant
increase in Pb accumulation in roots (255.60±4.80 mg kg−1), stem (124.07±2.84 mg kg−1),
and leaves (92.00±3.22 mg kg−1) was observed in T3 (15 mg L−1 ZnO NPs) for P. hydropiper.
Contrarily, ZnO NPs at 20 mg L−1dose suppressed plant growth, Pb accumulation, secondary
metabolites, and antioxidative enzyme activities. Moreover, a positive correlation was found
in Pb accumulation with free proline and secondary metabolite contents in plant tissues. These
results suggest that ZnO NPs at optimum concentration may augment efficacy of plants to
remove heavy metal from polluted water through nanophytoremediation.
Keywords: ZnO nanoparticles; Pb phytoaccumulation; Persicaria hydropiper L.; Hydroponic
growth; Phenolics

Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus

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