Foliar Application of Ascorbic Acid and Green-Synthesized Nano Iron for Enhancing Drought Tolerance and Antioxidant Defense in Common Beans

This study evaluated the effects of foliar-applied iron nanoparticles (FeNPs, 100 mg L⁻¹) and ascorbic acid (AsA, 400 mg L⁻¹) on the growth, photosynthetic pigments, and antioxidant defense mechanisms of common beans under optimal (100% FC) and water-restricted (50% FC) conditions. Under drought stress, both FeNPs and AsA significantly alleviated the negative impacts of water deficit, improving plant height, chlorophyll content, and carotenoid accumulation. FeNPs increased chlorophyll a by 60% and carotenoid content by 83.5%, while AsA enhanced ascorbate peroxidase activity (APX) activity by 44.8%, demonstrating its role in reducing oxidative stress. Additionally, FeNPs boosted catalase (CAT) and superoxide dismutase (SOD) activities by 198.2% and 17.3%, respectively. These treatments also significantly reduced malondialdehyde (MDA) concentration, with FeNPs-treated plants showing a 54.7% reduction compared to the control (P