Positive responses of strawberry (Fragaria × ananassa Duch.) explants to salicylic and iron nanoparticle application under salinity conditions

KEY MESSAGE: Salicylic acid and iron nanoparticles application improved morphological and growth-related characteristics of the strawberry plantlets′ under in vitro culture and Positive responses to salinity stress. Strawberry explants cv. Queen Elisa were cultured under in vitro conditions to monitor the application of salicylic acid (SA) and iron nanoparticles (INs) in response to salinity. Three levels of salinity (0, 50, and 100 mM NaCl), three levels of iron nanoparticles (0.0, 0.08, and 0.8 ppm), and three SA concentrations (0.0, 0.01, 0.05 mM) were applied. Salinity showed negative effects on growth parameters, pigment content, relative water content (RWC) and membrane stability index (MSI), and disturbed the ionic exchange in mature plants. The application of SA showed a positive and compensating effect that somewhat reversed the effects of salinity. INs, as a readily available alternative to iron sulphate, have also shown positive impacts on strawberry plants under salinity conditions. The application of both SA and INs improved all growth-related parameters and increased the pigment content, RWC, MSI, and iron and potassium contents of the mature plants, and decreased the content of sodium under salinity conditions. The highest concentration of INs (0.8 ppm) showed the highest positive effect for almost all measured parameters. While no statistical difference was detectable between high (0.05 mM) and medium (0.01 mM) levels of SA under salinity conditions, under non-stress conditions the difference was significant for growth-related parameters. Hence, if the aim is to produce strawberry explants or transplants using tissue culture, the application of higher SA levels is appropriate; but for decreasing the negative effects of salinity, medium levels of SA seem to be effective.