چکیده
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High salt levels are one of the significant and major limiting factors on crop yield and
productivity. Out of the available attempts made against high salt levels, engineered nanoparticles
(NPs) have been widely employed and considered as effective strategies in this regard. Of these NPs,
titanium dioxide nanoparticles (TiO2 NPs) and selenium functionalized using chitosan nanoparticles
(Cs–Se NPs) were applied for a quite number of plants, but their potential roles for alleviating the
adverse effects of salinity on stevia remains unclear. Stevia (Stevia rebaudiana Bertoni) is one of the
reputed medicinal plants due to their diterpenoid steviol glycosides (stevioside and rebaudioside A).
For this reason, the current study was designed to investigate the potential of TiO2 NPs (0, 100 and
200 mg L1) and Cs–Se NPs (0, 10 and 20 mg L1) to alleviate salt stress (0, 50 and 100 mM NaCl)
in stevia. The findings of the study revealed that salinity decreased the growth and photosynthetic
traits but resulted in substantial cell damage through increasing H2O2 and MDA content, as well
as electrolyte leakage (EL). However, the application of TiO2 NPs (100 mg L1) and Cs–Se NPs
(20 mg L1) increased the growth, photosynthetic performance and activity of antioxidant enzymes,
and decreased the contents of H2O2, MDA and EL under the saline conditions. In addition to the
enhanced growth and physiological performance of the plant, the essential oil content was also
increased with the treatments of TiO2 (100 mg L1) and Cs–Se NPs (20 mg L1). In addition, the
tested NPs treatments increased the concentration of stevioside (in the non-saline condition and
under salinity stress) and rebaudioside A (under the salinity conditions) in stevia plants. Overall,
the current findings suggest that especially 100 mg L1 TiO2 NPs and 20 mg L1 Cs–Se could be
considered as promising agents in combating high levels of salinity in the case of stevia.
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