Preparation of Nanofertilizer from Biogenic Zn-Nanoparticles Synthesized by Azotobacter spp. and its Impact on Growth Promotion of Coriandrum sativum

Two isolates of Azotobacter spp. were isolated from the agricultural soil habitat of Jejuri village, Pune, Maharashtra, and identified using morphological characterization and biochemical tests. Zinc nanoparticles (Zn NPS) were synthesized from Azotobacter spp. and characterized by UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and FESEM. XRD analysis showed the nanocrystalline form of zinc oxide NPs, and the Scherrer equation determined a mean crystallite size of approximately 42 nm. The FESEM spectra revealed the spherical shape and agglomeration of the biosynthesized nanoparticles. Various functional groups were involved in the capping and stabilization of the zinc oxide NPs, as confirmed by FTIR analysis. A pot experiment was conducted to study the effect of nanofertilizer prepared from zinc nanoparticles on parameters such as plant height, shoot length, root length, and dry leaf weight of Coriandrum sativum (coriander plant). In addition, parameters such as photosynthetic pigments, hormones, sugars, polyphenols, and proteins were tested. Mean values of measurements recorded on the 9th, 10th, 11th, and 12th days, along with standard deviation (SD) and percentage gain relative to the control measurements, were computed and reported. On the 12th day, the increase in height of the plant, length of the shoot, length of the root, and dry weight of the leaves in percentage were 9.24, 9.84, 10.86, and 11.71, respectively. On the 9th, 10th, and 11th days, the growth pattern was the same. To strengthen these results, advanced statistical analysis, such as analysis of variance (ANOVA), was performed and found that the growth in height of the plant, length of the shoot, length of the root, and weight of dry leaves significantly increased with respect to increasing days as well as increasing concentrations of nano fertilizer. Furthermore, to test significant differences in the mean chlorophyll content of both types of chlorophyll ‘a’ and chlorophyll ‘b’, a t-test for equality of population means was applied, and the results are reported. The results revealed that the nanofertilizer enhanced plant growth and health.