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Abstract
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Background: Drought is a major abiotic stress that restricts plant growth and efciency although some nutrients such as silicon improve drought tolerance by regulating the biosynthesis and accumulating some osmolytes. In this regard, a completely randomized factorial design was performed with three factors including two genotypes (‘Maragheh’ and ‘Kashan’), three concentrations of silicon dioxide nanoparticles (SiO2-NPs) (0, 50, and 100mg L−1 ), and fve concentrations of PEG (0, 25, 50, 75, and 100g L−1 ) with three replications. Results: The fndings showed that drought stress decreased protein content and it was improved by SiO2-NPs, so the genotype of ‘Maragheh’ treated with 100mg L−1 SiO2-NPs had the highest protein content. Under severe drought stress, had a higher membrane stability index (MSI) than ‘Kashan’, and the ‘Maragheh’ explants subjected to 100mg L−1 SiO2-NPs exhibited the uppermost MSI. The explants supplemented with 100mg L−1 SiO2-NPs sustained their photosynthetic parameters more in comparison with other treatments under drought stress conditions and as well as 100mg L−1 SiO2-NPs showed higher content of protein and proline of ‘Maragheh’ than ‘Kashan’. Drought stress reduced Fm, Fv/Fm, and Fv, while SiO2-NPs treatment enhanced these parameters. SiO2-NPs also improved water defcit tolerance by enhancing the activity of antioxidant enzymes such as catalase (CAT), peroxidase (POD), guaiacol peroxidase (GPX), and superoxide dismutase (SOD) and reducing lipid peroxidation and H2O2 concentration. Conclusions: According to the fndings, the genotype ‘Maragheh’ was more tolerance to drought stress than ‘Kashan’ by improving water balance, antioxidant enzyme activities, and membrane stability as it was obtained from the unpublished previous evaluation in in vivo conditions and we concluded based on these results, in vitro culture can be used for drought screening in Damask rose plants. The results of the current study revealed that the induced drought stress by
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