Agriculture Reference
In-Depth Information
Lu et al. (
2002
) showed the productive effect of mixture of SiO
2
and TiO
2
nanoparticles in
G. max
with increase in water and fertilizer uptake capacity and
stimulation of nitrate reductase and antioxidant activity. Studies demonstrating the
effect of nano-TiO
2
in promoting photosynthesis and growth in spinach have also
been conducted in which an increase in photosynthetic processes under both visible
and ultraviolet light has been reported due to the pivotal role of TiO
2
(Lei
et al.
2007
). Zheng et al. (
2005
) reported that TiO
2
nanoparticles have increased
73 % dry weight, threefold higher photosynthetic rate, and 45 % increment in
chlorophyll a after seed treatment in spinach. As suggested the reason of increment
in photosynthetic rate may be due to the increase in absorption of inorganic
nutrients which enhanced the utilization of organic substance and quenching of
oxygen-free radicals. Unlike most of the studies showing negative impact of
nanoparticles at higher concentration, Mahmoodzadeh et al. (
2013
) reported that
up to 2,000 ppm concentration of TiO
2
nanoparticles leads to an increased seed
germination and seedling vigor in
Brassica napus
.
Shah and Belozerova (
2009
) studied the effect of different metal nanoparticles
such as silicon (Si), palladium (Pd), gold (Au), and copper (Cu) on lettuce seed
germination. They conferred that nanoparticles showed positive influence at dif-
ferent concentration range such as Pd and Au at lower concentration, Si and Cu at
higher concentration, and Au and Cu in combined mixture. Likewise, in a field
study, Quoc Buu et al. (
2014
) reported an increased seed germination rate in
G. max
as compared to control when treated with nanocrystalline powder of iron, cobalt,
and copper at an extra low concentration. In addition, a marked increase was
observed in the chlorophyll index, number of nodules, and crop yield. Arora
et al. (
2012
) reported that foliar spray of gold on
Brassica juncea
plant in field
experiments showed positive effect as it resulted in increased plant height, stem
diameter, number of branches, number of pods, and seed yield. Interestingly, gold
nanoparticles also improved the redox status of treated plants. Suriyaprabha
et al. (
2012
) reported that treatment with SiO
2
nanoparticles in maize plants
significantly enhanced the plant dry weight and also enhanced the levels of organic
compounds such as proteins, chlorophyll, and phenols.
4.7 Uptake, Translocation, and Fate of Nano-fertilizers
in Plants
The uptake and fate of nano-fertilizers in plant is a growing field of research
interest. The uptake, translocation, and accumulation of nanoparticles depend on
the plant species, age, growth environment, and the physicochemical property,
functionalization, stability, and the mode of delivery of nanoparticles. Rico
et al. (
2011
) proposed a schematic representation of the uptake, translocation, and
biotransformation pathway of various nanoparticles along with possible modes of
cellular uptake in plant system (Figs.
4.1
and
4.2
).
