Application of zinc oxide nanoparticles immobilizes the chromium uptake in rice plants by regulating the physiological, biochemical and cellular attributes

Farwa Basit; Muhammad Mudassir Nazir; Muhammad Shahid; Saghir Abbas; Muhammad Tariq Javed; Tahir Naqqash; Yihan Liu; Guan Yajing

doi:10.1007/s12298-022-01207-2

Application of zinc oxide nanoparticles immobilizes the chromium uptake in rice plants by regulating the physiological, biochemical and cellular attributes

Physiol Mol Biol Plants. 2022 Jun;28(6):1175-1190. doi: 10.1007/s12298-022-01207-2. Epub 2022 Jul 10.

Authors

Farwa Basit^#¹, Muhammad Mudassir Nazir^#¹, Muhammad Shahid², Saghir Abbas³, Muhammad Tariq Javed³, Tahir Naqqash⁴, Yihan Liu¹, Guan Yajing¹

Affiliations

¹ Seed Science Center, Institute of Crop Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058 China.
² Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, 38000 Pakistan.
³ Department of Botany, Government College University, Faisalabad, 38000 Pakistan.
⁴ Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University, Multan, 60800 Pakistan.

^# Contributed equally.

Abstract

Zinc oxide nano particles (ZnO NPs) have been employed as a novel strategy to regulate plant tolerance and alleviate heavy metal stress, but our scanty knowledge regarding the systematic role of ZnO NPs to ameliorate chromium (Cr) stress especially in rice necessitates an in-depth investigation. An experiment was performed to evaluate the effect of different concentrations of ZnO NPs (e.g., 0, 25, 50, 100 mg/L) in ameliorating the Cr toxicity and accumulation in rice seedlings in hydroponic system. Our results demonstrated that Cr (100 µM) severely inhibited the rice seedling growth, whereas exogenous treatment of ZnO NPs significantly alleviated Cr toxicity stress and promoted the plant growth. Moreover, application of ZnO NPs significantly augmented the germination energy, germination percentage, germination index, and vigor index. In addition, biomass accumulation, antioxidants (SOD, CAT, POD), nutrient acquisition (Zn, Fe) was also improved in ZnO NPs-treated plants, while the lipid peroxidation (MDA, H₂O₂), electrolyte leakage as well as Cr uptake and in-planta accumulation was significantly decreased. The burgeoning effects were more apparent at ZnO NPs (100 mg/L) suggesting the optimum treatment to ameliorate Cr induced oxidative stress in rice plants. Furthermore, the treatment of ZnO NPs (100 mg/L) reduced the level of endogenous abscisic acid (ABA) and stimulated the growth regulator hormones such as brassinosteroids (BRs) possibly linked with enhanced phytochelatins (PCs) levels. The ultrastructure analysis at cellular level of rice revealed that the application of 100 mg/L ZnO NPs protected the chloroplast integrity and other cell organells via improvement in plant ionomics, antioxidant activities and down regulating Cr induced oxidative stress in rice plants. Conclusively, observations of the current study will be helpful in developing stratigies to decrease Cr contamination in food chain by employing ZnO NPs and to mitigate the drastic effects of Cr in plants for the sustainable crop growth.

Keywords: Physio-biochemical attributes; Phytohormones; Plant growth; Seed germination; Stress tolerance.