Effect of silicon on antioxidant responses of two grape genotypes (Vitis vinifera L.) under salinity stress conditions

Silicon (Si) mitigates the impact of salinity stress in plants and enhances salt tolerance in grapevines. This study investigated the Si (۳ mM Na۲SiO۳) impacts on reducing salinity stress (۵۰ –۱۰۰ mM NaCl) and its effects on the levels of toxic ions, enzymatic and non-enzymatic antioxidant activity, and modifications in the composition of phenolic compounds in two hydroponically cultured grape (Vitis vinifera L.) genotypes: Chawga and AghUzum. The presence of high salt levels resulted in a notable reduction in the height of the plants as well as in the fresh and dry weights of both the leaves and roots. Furthermore, in response to NaCl-induced stress, there was an increase in Cl- and Na+ levels, accompanied by a decrease in K+ and NO۳- concentrations. Exposure to NaCl stress led to a high accumulation of H۲O۲, MDA, proline, total soluble sugar, and glycine betaine in AghUzum compared to Chawga. Si regulated osmolyte levels, reduced membrane damage, and increased antioxidant activity. The results demonstrated that Si significantly reduced the toxicity caused by salinity; however, its impact is genotype-dependent. In Chawga, Si induced more tolerance to salt stress than AghUzum. Si made salt tolerance in Chawga by maintaining ionic balance, while in AghUzum, it was through the antioxidant enzyme activation. These results can help develop new strategies to protect grapevines from saline stress and explain how silicon makes different grape genotypes less sensitive to salt.

Keywords:

Salt stress , Vitis vinifera , Physiological changes , Si , Salt tolerance , Salt stress , Vitis vinifera , Physiological changes , Si , Salt tolera