Iron-manganese nanocomposites doped graphene quantum dots as growth promoter of wheat and its biomimetic activity.

This study describes the development of iron manganese doped graphene quantum dots (FeMnO₄@GQD) having peroxidase-like catalytic activity detected through chromogenic reaction in the presence of supplementary H₂O₂. Synthesized hetero-atoms doped GQD showed excellent peroxidase mimicking activity with a Vmax value of 9.91547 × 10^{− 6} (M/min) and Km value of 0.0491 mM towards substrate TMB (based on Hanes-Woolf kinetics) suggesting higher affinity towards the substrate than the natural enzyme (horseradish peroxidase). In another experiment, we systemically examined the efficacy of GQD and its nanocomposites on germination, vigor, and biochemical activity of bread wheat (Triticum aestivum). Prepared nanomaterials were applied at 200 and 500 µg/mL, initially through seed priming (solid matrix priming) and later through foliar spray on transplanted wheat seedlings grown on nutrient-free sand. The application of iron manganese nanocomposites (FeMnO₄) and FeMnO₄@GQD improve seed germination and maintain an optimum level of carbohydrates and protein contents that eventually promotes seedling growth. Different germination-related parameters were found to be influenced by the applied higher dose (500 µg/mL) of FeMnO₄@GQD. Seedling growth, plant biomass, and biochemical parameters like chlorophyll, carotenoid, sugar, protein, and phenolic content were stimulated by both FeMnO₄ and FeMnO₄@GQD applications. [ABSTRACT FROM AUTHOR]