Potassium silicate alleviates deleterious effects of salinity on two strawberry cultivars grown under soilless pot culture

• The effect of potassium silicate on two strawberry cultivars exposed to salinity was investigated.
• NaCl imposed oxidative damages to cell manifested as decreased MSI as well as increased MDA and H2O2.
• Supplementary potassium silicate counteracted the negative effects of salinity on strawberry cultivars.
• Mitigation effect of potassium silicate on most evaluated variables was more effective at 1000 ppm.

We aimed to understand the impact of two potassium silicate (K2O3Si) levels (1000 and 1500 ppm) on vegetative growth, physiological parameters and fruit yield of two strawberry cultivars under saline (50 mM NaCl) and non-saline conditions during 2014 and 2015. Supplementary Si counteracted the negative effects of salinity on dry matter, leaf area, and root length and volume. Leaf relative water content and chlorophylls content were also improved by application of K2O3Si under salinity. NaCl imposed oxidative damages to cell manifested as decreased membrane stability index (MSI) as well as increased malondialdehyde (MDA) and H2O2 content. Higher MSI as well as lower MDA and H2O2 in Si-supplied plants representing a systemic palliative effect of Si to salinity induced cellular injuries. Salinity led to an increase of proline and soluble carbohydrates suggesting a physiological osmotic strategy to increase salt tolerance. Reduction of proline content further supports the beneficial roles of Si in alleviation of the adverse effects of salt stress. Significant increase in activity of peroxidase (POD) and superoxide dismutase (SOD) enzymes was only observed during 2015 under saline conditions. The induction of antioxidant enzymes coincided with a decrease in concentration of MDA and H2O2. Salinity decreased fruit yield in both cultivars with a drastic reduction in Paros. K2O3Si nutrition could recover yield loss with almost a 50% increase in fruit weight per plant. Overall, our results suggest that drenching potassium silicate in the nutrient solution of strawberry plants could be considered as a routine strategy to maintain strawberry growth and yield under salinity.