Template-Type: ReDIF-Article 1.0 Author-Name: Shweta Alhan Author-Workplace-Name: Department of Environmental Science, Maharshi Dayanand University, Rohtak, (Haryana), India Author-Name: Naresh Tanwer Author-Workplace-Name: Central Pollution Control Board, Industrial Pollution Control-I Division, Delhi (Delhi), India Author-Name: Geeta Dhania Author-Workplace-Name: Department of Environmental Science, Maharshi Dayanand University, Rohtak, (Haryana), India Title: Exploring the Role of Molybdenum Nanoparticles in Catalyzing Nitrate Reductase Activity in Wheat (Triticum aestivum): An In Vitro Study Abstract: Nitrogen use efficiency (NUE) is a major determinant of crop productivity, yet substantial nitrogen losses during fertilizer application reduce agricultural sustainability and contribute to environmental pollution. Nitrate reductase (NR), a molybdenum-dependent enzyme, catalyses the first and rate-limiting step of nitrate assimilation, making molybdenum availability essential for efficient nitrogen metabolism. The present study aimed to synthesize and characterize molybdenum trioxide (MoO₃) nanoparticles and evaluate their catalytic influence on nitrate reductase activity in wheat (Triticum aestivum) under in vitro conditions. MoO₃ nanoparticles were synthesized using a wet chemical route followed by calcination at 500°C and characterized by UV-Visible spectroscopy, zeta potential analysis, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD). The synthesized nanoparticles exhibited characteristic optical absorption, moderate colloidal stability (-25 mV), crystalline MoO₃-specific functional groups, high elemental purity, and well-defined crystalline diffraction peaks, confirming successful nanoparticle synthesis. The catalytic effect of Nano-MoO₃ was assessed by measuring nitrate reductase activity at five concentrations (15, 30, 45, 60, and 75 ppm). Enzyme activity increased significantly from 1.21 ± 0.08 to 6.35 ± 0.15 µM NO₂⁻ g⁻¹ h⁻¹, reaching a maximum at 45 ppm, followed by a decline to 3.05 ± 0.10 and 2.48 ± 0.13 µM NO₂⁻ g⁻¹ h⁻¹ at 60 and 75 ppm, respectively. Statistical analyses confirmed normality and homogeneity of variance, while one-way ANOVA demonstrated a highly significant effect of Nano-MoO₃ concentration on nitrate reductase activity (p < 0.001). Tukey's HSD test identified 45 ppm as the optimum concentration for enzyme activation. These findings demonstrate that appropriately dosed Nano-MoO₃ enhances nitrate reductase activity and possesses considerable potential as a nano-enabled micronutrient for improving nitrogen assimilation and nitrogen use efficiency in wheat. Keywords: molybdenum nanoparticles, nitrate reductase, wheat, nitrogen metabolism, nano-fertilizer, in vitro enzyme assay Journal: Inventum Biologicum: An International Journal of Biological Research Pages: 41-51 Volume: 6 Issue: 3 Year: 2026 File-URL: https://journals.worldbiologica.com/ib/article/view/222 File-Format: text/html File-URL: https://journals.worldbiologica.com/ib/article/view/222/390 File-Format: Application/pdf Handle: RePEc:adg:ibijbr:v:6:y:2026:i:3:p:41-51