Iron oxide nanoparticles alleviate salt-alkaline stress and improve growth by modulating antioxidant defense system in cherry tomato

The integration of nanoparticles (NPs) into agriculture is altering traditional methods, enhancing productivity and sustainability. This study explores the application of iron oxide nanoparticles (FeONPs) to mitigate salt-alkaline stress in cherry tomatoes. We investigated FeONPs at three concentrations (FeONP25, FeONP50, FeONP100 mg/kg soil) in pot experiments under non-stress (NS) and salt-alkaline stress (SAS) conditions. SAS conditions decreased biomass and nutrients in untreated plants, a trend reversed by FeONPs. FeONPs treatments significantly boosted pigment levels under SAS, thereby increasing chlorophyll a (10.65–43.05%), chlorophyll b (7.19–41.33%), total chlorophyll (9.84–42.49%), and carotenoids (8.97–36.09%) compared to the control. FeONPs also reduced NPQ under stress, indicating enhanced photosynthetic efficiency. Oxidative stress markers (H₂O_2, O₂⁻, and MDA) were strongly induced in control plants but significantly declined with FeONPs treatments. Antioxidants and osmoregulatory substances significantly improved with FeONPs, thereby demonstrating their potential to alleviate SAS in cherry tomato plants.