PJB-2019-546
Effect of ZnO, SiO2 and composite nanoparticles on Arabidopsis thaliana and involvement of ethylene and cytokinin signaling pathways
Beenish J. Azhar, Asma Noor, Alveena Zulfiqar, Asyia Zeenat, Shakeel Ahmad, Iqbal Chishti, Zehra Abbas and Samina N. Shakeel
Abstract
This study encompasses the synthesis and characterization of ZnO, SiO2 and ZnO/SiO2 composite NPs by X-ray diffraction (XRD) and Fourier Transform infrared spectroscopy (FTIR) followed by analyzing the effects of these NPs on growth of Arabidopsis thaliana at physiological and molecular levels by transcript analysis of selected genes of ethylene / cytokinin pathways. Our data showed toxic effects of ZnO at all concentrations except 10mg/L, while SiO2 promoted the seedlings growth at almost every concentration. The transcript analysis of ethylene and cytokinin regulated genes provided evidences that ZnO was toxic at all levels except 10mg/L as it induced the expression of ethylene response genes; ethylene being a stress hormone and reduced the expression of cytokinin response genes, cytokinin being positive regulator of growth through involvement in chlorophyll synthesis. SiO2 application was nontoxic at all concentrations, determined through less expression of ethylene biosynthesis genes and higher expression of cytokinin genes that showed more than two-fold induction in SiO2 NP treated seedlings. The chlorophyll contents were decreased to almost 50 percent in response to different concentrations of ZnO while remained unaffected or increased by applying SiO2 NPs. Combined effect of ZnO and SiO2 i.e. Composite NPs reduced the toxicity caused by ZnO alone which was responsible in reducing the chlorophyll content, overall growth of plant and ethylene production determined through the expression of ethylene regulated genes
To Cite this article:
Azhar, B.J., A. Noor, A. Zulfiqar, A. Zeenat, S. Ahmad, I. Chishti, Z. Abbas and S.N. Shakeel. 2021. Effect of ZnO, SiO2 and composite nanoparticles on Arabidopsis thaliana and involvement of ethylene and cytokinin signaling pathways. Pak. J. Bot., 53(2): DOI: http://dx.doi.org/10.30848/PJB2021-2(40)
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