Enhancing strawberry salt stress tolerance: morphophysiological responses to different silicon rates and sources

Salinity stress is a critical environmental factor that significantly reduces strawberry productivity. The aims of the present study were to evaluate the efficacy of four foliar-applied silicon (Si) sources such as nano-silica, organic silica, potassium silicate, and stabilized silicic acid and rates including zero, 10, and 30 mg Si L^- 1 on morphological properties of strawberries in two salinity levels (0 and 50 mM NaCl). A factorial experiment in a randomized complete block design with three replications was conducted. Key physiological parameters such as chlorophyll contents, free proline, and fruit yield were measured. Results showed that stabilized silicic acid and potassium silicate at 30 mg L^- 1 significantly enhanced photosynthetic pigment concentrations, reduced oxidative stress, and improved yield under salt stress. Additionally, Vis-NIR data coupled with partial least squares regression (PLSR) moderately predicted leaf Si content under saline conditions (R² = 0.453 and MSE = 1.94). These findings highlight the potential of Si fertilization to mitigate salinity impacts in strawberry, while precision spectral tools such as Vis-NIR spectroscopy can support non-destructive monitoring of Si-induced physiological responses.