Deciphering the synergistic potential of mycogenic zinc oxide nanoparticles and bio-slurry formulation on phenology and physiology of Vigna radiata

Nanobiofertilizers have emerged as an innovative tool for enhancing crop productivity. In the current research, zinc oxide nanoparticles (ZnONPs) were mycosynthesized using cell-free supernatant of Trichoderma harzianum and optimized for physical parameters. Characterization using UV-Visible spectroscopy, dynamic light scattering analysis, zeta potential analysis, X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy-EDX, and HR-Transmission electron microscopy confirmed the formation of ZnONPs with flower-like morphology and average size of 314 nm. The average zeta potential value of the ZnONPs was +1.9 mV indicating the formation of neutral NPs. FTIR peak at 401 cm(-1) revealed the presence of ZnONPs. XRD analysis confirmed the hexagonal wurtzite crystalline nature of the ZnONPs. The effect of ZnONPs at 10-1,000 ppm combined with liquid bio-slurry (BS) was studied on seed germination and growth of Vigna radiata. Combination of 250 ppm ZnONPs and BS at 1:2 ratio showed 22.6% increase in shoot length as well as 18.4% increase in root length as compared to control in in vitro studies. In Vivo pot experiments showed no significant difference in secondary metabolites after 60 days, but the root length increased by 38.9% and shoot length increased by 46.95% compared to the control.