Green Synthesis of Biogenic Nano Zerovalent Iron Using <i>Cleistocalyx nervosum</i> Leaf Extract for Enhancing Peanut Seed Germination and <i>Basella alba</i> Growth

In this study, biogenic nano zerovalent iron (bio-nZVI) was synthesized through a green approach using Cleistocalyx nervosum (C. nervosum) leaf extract for use as a nanopriming agent for improving peanut seed germination and Basella alba growth. The scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR), and X-ray diffraction (XRD) results demonstrated that bio-nZVI was successfully synthesized. The as-synthesized bio-nZVI had a spherical shape with a size ranging from 80 to 350 nm. The prepared bio-nZVI had a core-shell structure with a core of Fe⁰ and a shell of Fe₂O₃, and this core-shell structure was covered by an organic layer derived from the leaf extract. The synthesized bio-nZVI was applied to peanut seeds and Basella alba plants at concentrations ranging from 10 to 320 mg/L to enhance seed germination and plant growth. The results demonstrated that bio-nZVI at optimal concentrations of 20-40 mg/L could significantly improve peanut seed germination and promote Basella alba growth. However, no significant effect on enhancing peanut seed germination and Basella alba plant growth was observed when applying a bio-nZVI solution at higher concentrations. These findings suggest that bio-nZVI could be a promising germination promoter and eco-friendly growth enhancer for agricultural applications; thereby, it has great potential for increasing crop productivity and meeting demand for grain worldwide.