The synthesized zinc oxide/silicon dioxide@graphene oxidenanocomposite (ZnO/SiO2@GO) enhances quinoa tolerance to high salinity

The nanocomposite zinc oxide/silicon dioxide@graphene oxide (ZnO/SiO ₂ @GO) was synthesized by the decoration of ZnO nanoparticles (NPs) and SiO ₂ NPs onto GO. The synthesized nanocomposite was used as seed soaking for modulation of tolerance of quinoa ( Chenopodium quinoa ) to high salinity stress. Seeds were soaked in 40 mg ZnO/SiO ₂ @GO L ^− 1 of the nanocomposite for 6 h thereafter NaCl was applied at 200 mM, 400 mM and 500 mM -on the 10th day of sowing- for a duration of 21 days. The results demonstrated that high NaCl (400 mM and 500 mM) significantly reduced growth parameters, photosynthetic pigments, protein, insoluble and total sugars, phenolics and activities of peroxidase and catalase. Conversely, soluble sugars, lipid peroxide (malondialdehyde, MDA) and hydrogen peroxide (H ₂ O ₂ ) levels were elevated, with the effects being more pronounced at higher NaCl concentrations. However, using ZnO/SiO ₂ @GO as a seed priming agent effectively mitigated the adverse effects of NaCl on these parameters. Growth was enhanced, while reductions in pigments, protein, sugars, phenolics, and enzymatic activities were counteracted. Additionally, elevated levels of soluble sugars, MDA, and H ₂ O ₂ were suppressed, approaching control levels. These findings highlight the severe impacts of high salinity stress and indicate that treatment with the ZnO/SiO2@GO nanocomposite can mitigate these adverse effects. Therefore, this nanocomposite could be considered a safe and efficient protectant to enhance quinoa's tolerance to high NaCl levels.