Foliar Application of Iron Oxide Nanoparticles Enhances Morphophysiological Characteristics and Yield Performance of Capsicum annuum L. in a Controlled Environment

Abstract

Iron (Fe) is an essential micronutrient that plays a vital role in several plant physiological processes. Nevertheless, iron deficiency remains a significant challenge in chili plants, particularly affecting their fruitproduction. Therefore thisstudy aimed to characterize the physicochemical of iron oxide nanoparticles (IONPs) and investigatethe effects of foliar-applied IONPson the growth, physiological responses, and yield parameters of Capsicum annuum. The physicochemical characteristics of IONPswere analyzed using a High-Resolution Transmission Electron Microscope and scanning electron microscopy with energy dispersive X-ray spectroscopy. Six IONPsconcentrations (0, 50, 100, 200, 400, and 800 mg/L) were applied through foliar spray on chili plantsduring four critical growth stages: vegetative growth, flowering, fruit development, and maturity. The findings revealed the spherical, uniform surface structures with an average size of 12–20 nm and 58.2% of iron composition. On the other hand, the field evaluation demonstrated that foliar application of IONPsat concentrations between 200 mg/L significantly enhanced plant height and photosynthesis activity compared to control treatment. In terms of yield, 400 mg/L IONPs resulted in the highest fruit yield compared to control treatments.This research establishes the effectiveness of IONPsas a growth promoter and yield enhancer in chili cultivation, with optimal concentrations identified for commercial application.Future research should focus on long-term effects and environmental impacts to develop comprehensive application guidelines for sustainable agricultural practices.