Alleviation of the effect of salinity on pomegranate seedlings by priming foliar spray of chitosan-silicon nanoparticles (CTS-SiO2 NPs)

Abstract Background Today, improving the nutritional status of plants using external supplements, particularly based on nanotechnology, is of great importance to compensate for the damage caused by abiotic stresses. Salinity is one of the chief environmental stresses limiting the growth and yield of crops by reducing the osmotic potential and disrupting the absorption of water and nutrients. The present study was conducted to compare the priming effect of foliar spraying the following treatments: silicon nanoparticles (SiO2 NPs; 50 mg L−1), chitosan nanoparticles (CTS NPs; 0.1%), chitosan-silicon nanoparticles (CTS-SiO2 NPs; 25 and 50 mg L−1) and distilled water (control). These treatments were assayed on reducing the effects of sodium chloride (NaCl) salinity stress (0 and 150 mM) on two-year old pomegranate seedlings. Results The results showed that under salinity stress, foliar application of combined chitosan-silicon treatment provided a better role in moderating the negative effects of stress than the single use of these nanomaterials and improved seedling height (HT), diameter (DIA), leaf area (LAI), fresh and dry weight, chlorophyll a and carotenoid content, membrane stability index (MSI), APX, concentrations P, K, and K/Na ratio. The combined chitosan-silicon treatment also reduced the rate of electrolyte leakage (EL) under stress conditions. Chitosan foliar application alone increased leaf number (LN) and reduced nitrogen and hydrogen peroxide (H2O2) levels under stress. Silicon also reduced the amount of MDA and Na. Conclusions Therefore, it seems that the application of CTS-SiO2 NPs could be considered as an effective method to reduce the negative effects of salt stress on pomegranate. This study represents one of the early scientific investigations demonstrating the synergistic potential of CTS-SiO2 nanoparticles in boosting pomegranate tolerance to salinity stress, highlighting its novelty while acknowledging that further research is needed for definitive confirmation.