Agriculture Reference
In-Depth Information
3.4 Nano-fertilizer Research
Nano-fertilizer is quite innovative, and recent publications strongly supported that
there is a lot to be done before the technology reaches the farm gate. Almost all
essential nutrients have been attempted to be delivered through nano-adsorbents. In
most cases, clays and other aluminum silicates have been used as effective adsor-
bents to deliver nutrients. It has been unequivocally demonstrated that the size
reduction by physical or chemical methods increased the surface mass ratio;
thereby, bountiful of nutrient ions get adsorbed and desorbed slowly and steadily
for an extended period of time (Table
3.1
). This table summarizes the literature
review on nano-fertilizer formulations published in the recent past. Despite these
literatures are in support of nano-fertilizer technology, still the data are yet to
establish whether nutrient release is adjusted or regulated in accordance with the
crop demand.
3.5 Mode of Entry
Plant cell wall acts as a barrier for easy entry of any external agents including
nanoparticles into the plant cells. The sieving properties are determined by pore
diameter of cell wall ranging from 5 to 20 nm (Fleischer et al
.
1999
). Hence, only
nanoparticles with diameter less than the pore diameter of the cell wall could easily
pass through and reach the plasma membrane. There is also a chance for enlarge-
ment of pores or induction of new cell wall pores upon interaction with engineered
nanoparticles which in turn enhance nanoparticle uptake. Further internalization
occurs during endocytosis with the help of a cavity-like structure that forms around
the nanoparticles by plasma membrane. They may also cross the membrane using
embedded transport carrier proteins or through ion channels. In the cytoplasm, the
nanoparticles are applied on leaf surfaces; they enter through the stomatal openings
or through the base of the trichomes and then translocated to various tissues.
However, accumulation of nanoparticles on photosynthetic surface causes foliar
heating which results in alterations of gas exchange due to stomatal obstructions
that produce changes in various physiological and cellular functions of plants
(Fernandez and Eichert
2009
).
3.5.1 Nanocapsules Enter Plants Through Stomata Orifices
and Prevent Infection
The crop protection agents (CPAs) are nano-encapsulated, and the resulted polymer
nanocapsules are sprayed onto the leaf tissue. These nanocapsules enter the plant
through the stomata orifices. The nanocapsule
s chemical bonds of the polymer
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