Mechanistic Pathway of Green Synthesized Co2O3/CuO Nanocomposites in Enhancing Vigna Radiata Germination and Seedling Development

Abstract

Green synthesis provides an environmentally considerate approach for producing metal oxide nanomaterials for agricultural applications. This study synthesized cobalt oxide/copper oxide (Co₂O₃/CuO) nanocomposites using Cannabis sativa leaf extract as a natural reducing and stabilizing medium and evaluated their effects on Vigna radiata germination and early seedling development. The synthesized materials were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, ultraviolet-visible spectroscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The analyses indicated the formation of crystalline Co₂O₃/CuO nanocomposites with nanoscale morphology and a generally homogeneous elemental distribution. Seed germination assays were conducted using 25 seeds per treatment at nanocomposite concentrations of 0, 1, 2, and 3 mg. Germination and seedling growth varied with concentration. The 3 mg treatment produced the highest reported germination percentage of 92%, compared with 80% in the untreated control, and was associated with the greatest reported seed Vigor index. Root and shoot development also increased across the tested treatments. The proposed pathway attributes these responses to improved water uptake, micronutrient availability, activation of hydrolytic processes, and regulation of reactive oxygen species. Within the tested conditions, the findings indicate that plant-mediated Co₂O₃/CuO nanocomposites may support early seedling establishment, although dosage optimization and further safety evaluation are required before wider agricultural application.