Evaluation of Microbially Synthesized Zinc Nanoparticles on Growth and Yield of Maize (Zea mays L.)
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Date
2016-06
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University of Agricultural Science, Dharwad
Abstract
Soil samples from the fields of MARS, Dharwad were collected with the aim of isolating zinc solubilizing microorganisms. Available zinc content of soil was taken as base for sample collection. Out of 30 samples collected 15 samples from 0.1 to 0.38 ppm, 6 from 1.3 to 2.0 ppm and 9 from 2.1 to 2.5 ppm. Higher population of zinc solubilizers were found in lower zinc containing soil samples. Fungal isolates showing higher zone of zinc solubilization and higher zinc metal tolerance were selected and analyzed for the synthesis of zinc nanoparticles (ZnNP’s) by the incubation method.
Characterization of microbial synthesized ZnNP’s was done by UV-Visible spectrometer, which exhibited a peak at 260 nm. Confirmation of this ZnNP’s was further done by Atomic Force Microscope which shown spherical shape. X-ray Diffraction (XRD) analysis revealed the presence of ZnNP’s with the 2Ɵ values of 31.74° and 36.23°. The sharp peaks exhibited in XRD graph indicated the presence of capping agent from the mother protein of the fungus. Out of 30 isolates, two fungal isolates viz., 3F and 9F were potent of producing zinc nanoparticles in size range of 20 to 60 nm.
A pot culture experiment was conducted to study the effect of microbial synthesized and chemical synthesized ZnNP’s on growth and yield parameters of maize. ZnNP’s were applied as foliar spray at 30 and 60 days after sowing at different concentrations ranging from 250 to 1250 ppm. Microbial synthesized ZnNP’s spray of 750 ppm exhibited higher response of increased chlorophyll content and yield parameters over all other treatments. Soil enzyme activity of dehydrogenase and phosphatase were high in treatment receiving 750 ppm of microbial synthesized ZnNP’s.
From the present study it is inferred that microbial synthesized ZnNP’s were more beneficial than chemical synthesized ZnNP’s at the same concentration of application. Foliar spray of 750 ppm was found to be optimum concentration for better growth and yield parameters of maize.