Iron Oxide Nanoparticles for Photosynthetic Recovery in Iron-Deficient ‘Micro-Tom’ Tomato Plants

In plant tissues, nanoparticles can stimulate the production of reactive oxygen species (ROS), which, in excess, cause cellular toxicity by damaging membranes, chloroplasts, and DNA. However, they can also activate antioxidant mechanisms, aiding metabolic recovery under oxidative stress. In agriculture, iron oxide (nFe) nanoparticles stand out for their gradual release of the nutrient, preventing leaching and increasing productivity. This study aims to investigate whether iron oxide nanoparticles are effective alternatives for overcoming iron deficiencies, mitigating oxidative stress and restoring metabolic functions, while maintaining photosynthesis. The high H2O2 concentration observed in nFe 500 mg L−1 (nFe 500) suggests that Fe, after being transported by the nanoparticles to the leaves, may have acted as a cofactor for antioxidant enzymes involved in H2O2 decomposition, reducing malondialdehyde concentration (MDA). Maintaining low oxidative stress suggests that H2O2 may function not only as a stress indicator but also as a signaling molecule in intracellular processes. nFe 500 suggests the ability of plants to utilize released Fe2+/Fe3+, restoring photosynthetic function in iron-deficient plants.