Investigating the Synergistic Interactions Between AgNPs and NiCl₂ on the Morpho-Physiological Trajectories of Zea mays L. Through Comprehensive Characterization at Seedling Stage

Green synthesis of nanoparticles (NPs) is preferred for its affordability and environmentally friendly approach. This study explored the synthesis and characterization of silver NPs (AgNPs) and examined their impact on the growth of Zea mays, both alone and in combination with nickel chloride (NiCl₂). A methanolic leaf extract was combined with silver nitrate to synthesize AgNPs. Characterization of NPs was carried out through UV-vis spectroscopy, FT-IR, x-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). Eleven treatments (T1-T11) were made, and Z. mays seeds were subjected to NiCl₂ in pots after being soaked in AgNPs solution. Treatments were arranged to evaluate the effects of NiCl₂ (T1-T3), AgNPs (T4 and T5), and the interactive effects of AgNPs and NiCl₂ (T6-T11) on the planted seeds. UV-vis peaks at 410 nm confirmed the presence of AgNPs. The crystalline nature of AgNPs was confirmed through XRD analysis, and the presence of functional groups from biomolecules and capping agents was shown in FT-IR. The morphology of the NPs and elemental analysis were conducted using SEM and EDS, respectively. The size of the NPs was found 25-50 nm using Nano Measurer software. Growth inhibition was noticed in NiCl₂-treatments T1-T3. Maximum growth and 100% seed germination were observed in NP-treated seeds (T4 and T5). These two treatments also showed the highest germination index, root/shoot growth, and fresh/dry weights. In treatments T6-T11, the interaction between NiCl₂ and AgNP-soaked seeds showed that while AgNP concentrations alone promoted growth, this enhancement was suppressed by the presence of NiCl₂ in the soil. The inhibited values of T6-T11 were still greater than the control, indicating that soaking Z. mays seeds in AgNPs enhanced growth and mitigated nickel stress in the soil. Pigments, carbohydrates, and protein contents were highest in T4 and T5, whereas NiCl₂ reduced these values. Synthesized AgNPs could enhance Z. mays growth and reduce nickel stress at the applied amounts. Further investigation is required to determine the mechanisms of action of AgNPs and NiCl₂ in enhancing or reducing Z. mays seedling growth and yield.