EFFECT OF ZINC OXIDE NANOPARTICLES ON GERMINATION, GROWTH AND YIELD OF MAIZE (Zea mays L.)
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Date
2017
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Publisher
AAU, Anand
Abstract
The present investigation was undertaken to investigate the effect of ZnO
nanoparticles (ZnO NPs) on seed germination, growth and yield of maize. The study
included four sequential experiments: (1) synthesis and characterization of ZnO NPs;
(2) effect of different concentrations of ZnO NPs on germination of maize seeds; (3)
effect of seed treatment with ZnO NPs on growth and yield of maize; and (4) effect of
foliar application of ZnO NPs on growth and yield of maize under microplot conditions.
In first experiment, ZnO NPs were synthesized, using oxalate decomposition
method and characterized by XRD, TEM, SEM, DLS, TGA and UV-vis spectroscopy
analysis. The instrumental analysis results clearly indicated that synthesized ZnO NPs
were of 65 nm particle size, nanorods, monodispersed, highly pure, and stable. The
particle size estimated by XRD and DLS were in good agreement with TEM, SEM and
UV-Vis spectroscopy results. Thermo-gravimetric analysis (TGA) results confirmed
the calcination temperature as more than 400 °C.
Synthesized ZnO NPs were tested for their efficacy for seed treatment of maize
in second experiment where in 3 levels each of ZnO NPs and bulk ZnO concentration
(500 ppm, 1000 ppm and 2000 ppm) along with ZnO slurry were repeated thrice in
completely randomized design (CRD). Seed germination test was carried out by paper
towel method of seed incubation for 9 days following standard protocol. Soaking time
for maize seeds with different Zn treatment was optimized at 2 hrs as there was no
significant difference from 4 hrs soaking with respect to seed vigour. Results revealed
that ZnO NPs at 1000 ppm concentration significantly increased seed germination, root
length and seedling vigour index over no Zn. However, higher concentration of ZnO
nanoparticles i.e. 2000 ppm reduced the root length and seed vigour.
Abstract
ii
Consequently, microplot study was conducted during Rabi and repeated during
summer seasons of the year 2015–2016 with 8 seed Zn treatments: no Zn; 500, 1000,
2000 ppm concentrations each of ZnO NPs and bulk ZnO, and ZnO slurry replicated
three times in CRD. Results of this experiment indicated that seed treatment with ZnO
NPs at 1000 ppm registered the highest grain, stover, and dry matter yield of maize.
Further, seed treatment with ZnO NPs either at 1000 and 2000 ppm recorded the highest
and statistically at par enhancement in grain, stover and root Zn concentrations. Zinc
uptake, partitioning and accumulation factor results corroborated the higher Zn
accumulation in grain. However, higher concentration of ZnO NPs caused detrimental
effect on germination and yield of maize. Important soil properties viz. pH, EC, OC (%)
and DTPA-extractable micronutrients contents were not affected significantly by any
of seed Zn treatments.
The effect of foliar application of three levels ZnO NPs (500, 1000, 2000 ppm)
along with corresponding concentrations of bulk ZnO and 0.5% ZnSO4 on maize was
investigated under microplot conditions for two consecutive seasons. Results suggested
that two foliar application of ZnO NPs to maize at 30 and 45 days of sowing proved to
be significantly superior in enhancing grain, stover and dry matter yield of maize, grain,
stover and root Zn concentration and uptake by maize, however, the results were at par
with 2000 ppm ZnO NPs. Like seed treatment experiment, ZnO NPs application did
not show any significant change in soil properties like pH, EC, OC (%) and DTPA-Zn.
The overall finding suggested that seed treatment with ZnO NPs at 1000 ppm
proved effective in increasing seed germination, seedling length, seedling vigour, plant
growth, grain, stover, dry matter yield, grain Zn concentration of maize. yield, stem and
root growth. If applied foliarly, ZnO NPs at 1000 ppm registered significantly enhanced
grain yield, Zn content and uptake by maize crop however, higher dose i.e. 2000 ppm
proved statistically at par. Thus, use of ZnO NPs at 1000 ppm was found beneficial in
increasing growth parameters and yield of maize over traditional application through
ZnSO4. However, the delivery mechanism may be improved upon to avoid health
hazards, if any due to the use of nanoparticles.
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Keywords
agriculture, soil science, agricultural chemistry, study