Iron Oxide Nanoparticles as a Tool for Enhancing Rapeseed Viability Under Excess Water Conditions

Flooding is a critical abiotic stressor that adversely impacts crop growth, including rape-seed (Brassica napus L.). Iron oxide (Fe₃O₄) nanoparticles (NPs) are emerging as a promising approach for mitigating such environmental stressors. This study aimed to assess the potential of soil-applied Fe₃O₄ NPs to alleviate the adverse physiological effects of flooding on rape-seed. Under controlled climate chamber conditions, plants were subjected to flooding following a pre-treatment application of Fe₃O₄ NPs at concentrations of 0, 50, and 100 mg/L. Results demonstrated that the 50 mg/L treatment significantly mitigated flooding stress, evidenced by increased total chlorophyll content, improved root development, and enhanced scavenging of reactive oxygen species (ROS), such as hydrogen peroxide (H₂O₂). These antioxidant mechanisms reduced oxidative stress, thereby preserving cellular integrity and photosynthetic function. However, the beneficial effects were strictly dose-dependent; the 100 mg/L concentration exhibited diminished efficacy and induced phytotoxicity compared to the optimal 50 mg/L dosage. These findings demonstrate that optimised, low-concentration Fe₃O₄ NP applications can effectively enhance rapeseed resilience to flooding. Future field studies are required to validate these outcomes and elucidate the underlying mechanisms for practical agricultural implementation.