Nano-zinc oxide (ZnO)-polymer seed coatings and their effect on soil microbes in maize (Zea mays L.)
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Date
2020
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Punjab Agricultural University, Ludhiana
Abstract
The present work aimed for the synthesis of ZnONPs from zinc acetate or zinc chloride as
precursor salts by using various reducing agents such as natural polymers (starch, cellulose,
potato-extract), bovine serum albumin, and thiourea. On UV-Vis absorption spectroscopy
analysis, the prepared ZnONPs exhibited characteristic absorption peaks ranging from 210 to 360
nm wavelength. The FT-IR spectroscopy of the synthesized ZnONPs depicted presence of Zn
metal-oxide functional groups. Transmission electron microscopy analysis revealed quasispherical
shapes of ZnONPs with an average particle size of <100 nm. The synthesized ZnONPs
were also evaluated for their antimicrobial potential for plant beneficial and phyto-pathogenic
bacterial and fungal cultures. Wet-chemistry derived ZnONPs (at 40 mg L-1) exhibited
antimicrobial activity against Dickeya sp. while at 20 mg L-1 concentration radial mycelial growth
of Macrophomina phaseolina was inhibited. Apart from antimicrobial potential, the free radical
scavenging or antioxidant activity of prepared ZnONPs as determined through DPPH radical
scavenging method. It was observed to be vary considerably among the ZnONPs synthesized
using different reducing agents and hence is anticipated to positively affect seed germination. The
effect of application of ZnONPs as seed priming and coating treatment on germination and
seedling growth traits was evaluated for two maize varieties PMH-1 and J-1006 using different
concentrations (0, 5, 10, 20, 40 mg L-1) of ZnO NPs and bulk ZnSO4 suspensions under
laboratory conditions. Seed coating with 20 mg L-1 of ZnONPs exhibited significantly higher
percent germination, root and shoot length, and fresh and dry weight of root besides number of
lateral roots of the maize seedlings (variety J-1006) as compared to bulk ZnSO4 treatments.
Further, ZnONPs priming and coating treatments were also evaluated for enhancing vegetative
growth and yield attributing parameters under field conditions during spring and kharif seasons in
the year of 2017-18 and 2018-19. The application of ZnONPs (at 40 mg L-1 concentration)
significantly enhanced the total chlorophyll content, available soil nutrient content (Nitrogen and
Phosphorus), improved the total soil microbial counts and soil enzyme activities(dehydrogenase,
and acid and alkaline phosphatase enzyme activities). Whereas, a significant increase in the
available soil potassium, and zinc contents and numerical increase in vegetative and yield
parameters (number of plants, plant height, stover yield, plant biomass) was recorded on treatment
of seeds with ZnONPs at 20 mg L-1 in maize variety J-1006 as compared to bulk ZnSO4 and
control treatments. These findings suggest positive effect on growth and yield attributing
characters in maize on seed priming and coating with ZnONPs. Therefore, use of ZnONPs at low
concentrations as seed priming/ coating agent can effectively improve productivity and soil health.
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Citation
Tondey, Manisha (2020). Nano-zinc oxide (ZnO)-polymer seed coatings and their effect on soil microbes in maize (Zea mays L.) (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.