Agriculture Reference
In-Depth Information
under stress and then permeate into the cells (Uzu). There is also a chance
for enlargement of pores or induction of new cell wall pores upon interac-
tion with engineered nano-particles, which in turn enhance nano-particles
uptake. Further Internationalization occurs during endo-cytosis with the
help of a cavity like structure that form around the nano-particles by plas-
ma membrane. They may also cross the membrane using embedded trans-
port carrier proteins or through ion channels. When nano-particles are ap-
plied on leaf surface, they enter through the stometal openings or through
the bases of trichomes and then translocated to various tissues (Goldbach;
Tilney, 1991) After entering the cells, NPs may be able to transport be-
tween cells via plasmodesmata, which are microscopic channels of plants
traversing the cell walls and enabling transport and communication be-
tween cells. Plasmodesmata or intercellular bridges were reported to be
cylindrical channels about 40 nm in diameter (Jia et al., 2005). Thus, NPs
with diameter less than 40 nm may enter and transport in the plant cells
through the plasmodesmata once they are in the plant cells. In the cyto-
plasm, the nano-particles may bind with different cytoplasmic organelles
and interfere with the metabolic processes at that site (Lee et al., 2008).
Plant uptake can be a critical transport and exposure pathway of NPs in the
environment. Interactions between plants and NPs, such as the mechanism
of uptake and translocation and the interactions between the NPs and plant
tissues at the molecular and cellular level, merit further investigations.
A recent study showed significant uptake of nano-sized copper (nCu)
by
Phaseolus radiates
(mung bean) and
Triticum aestivum
(wheat), re-
spectively (Xing, 2008). Transmission electron microscopy analysis
showed that Copper nano-particle was absorbed and agglomerated into the
cytoplasm of the root cells and the extent of absorption depended on the
concentration of the copper nano-particle deposited on the roots' surface.
Another study found individual ZnO nano-particles in endodermal and
vascular cells of rygrass (Jin et al., 2008). Signifi cant uptake, transloca-
Signiicant uptake, transloca-
tion and accumulation of Fe
3
O
4
nano-particle in the roots and leaves of
Cucurbita maxima
(pumpkin) has also been reported without any effect on
growth and development of the test species (Wilson et al., 2002). There-
fore, some uptake of nanoparticles by plants is very possible. However,
little is known about the maximum nano-particle size amenable for plant
uptake, and how uptake kinetics and toxicity are affected by plant type
and rhizospheric chemistry. Recent research highlights the importance
of transition metals that adsorb to nano-particles and promote oxidative
Jin et al., 2008). Signifi cant uptake, transloca-
2008). Signifi cant uptake, transloca-
Signifi cant uptake, transloca-
