Potential effects of metal oxide nanoparticles on leguminous plants: Practical implications and future perspectives

The use of nanoparticles in agriculture is increasing due to their ability to readily enter plants. Among these nanoparticles, metal oxide nanoparticles (MONPs) have garnered significant attention owing to their unique attributes such as stability and catalytic activity. Extensive studies have demonstrated the positive effects of various MONPs, including iron oxide (Fe₂O₃ or Fe₃O₄), copper oxide (CuO), zinc oxide (ZnO), titanium dioxide (TiO₂), cerium oxide (CeO₂), silicon dioxide (SiO₂), and magnesium oxide (MgO) on the growth and productivity of legume plants in normal and abiotic stress conditions. These nanoparticles enhance symbiotic interactions with bacteria, photosynthesis, nutrient uptake, and nitrogen fixation. However, excessive utilization of MONPs can have detrimental consequences, including reduced photosynthesis, nitrogen fixation, and altered gene expression, leading to diminished crop yield. To ensure the safe and effective application of MONPs, it is imperative to consider factors such as MONP type, concentration, and exposure method. The main objective of this review is to provide a comprehensive overview of the current research landscape concerning the role of MONPs and their effects on leguminous plants. Furthermore, it aims to identify potential avenues for future research in this domain. By addressing these aspects, this review endeavors to enhance our understanding of the implications and potential risks associated with the agricultural use of MONPs, facilitating informed decision-making and promoting sustainable practices.