Mn 3 O 4 Nanozymes Mitigate Salt Stress in Tomato ( Solanum lycopersicum ) by Scavenging Reactive Oxygen Species and Enhancing Photosynthesis

The mitigation of salinity stress by Mn 3 O 4 nanoparticles (NPs) has been reported in plants, yet their integrated effects on tomato─spanning seed germination, vegetative growth, fruit yield, and underlying molecular mechanisms─remain largely unexplored. This study employed physiological, transcriptomic, and metabolomic analyses to systematically evaluate tomato responses to 100 mM NaCl stress following Mn 3 O 4 NP application. Seed priming with 100 mg/L Mn 3 O 4 NPs significantly enhanced the germination rate by 103.02% ( p <0.05), while foliar spraying significantly improved seedling biomass and chlorophyll content and reduced oxidative stress markers. Under saline conditions, Mn 3 O 4 NP treatment increased fruit yield by 19.05% ( p <0.05). Multiomics data revealed that Mn 3 O 4 NPs induced coordinated upregulation of pathways related to systemic acquired resistance, phytohormone signaling, and antioxidant defense. These findings clarify the physiological and molecular basis of Mn 3 O 4 NP-induced salt tolerance and provide a foundation for developing nanoenabled strategies to enhance crop performance in saline environments.