Agriculture Reference
In-Depth Information
surface (Taladriz-Blanco et al.
2013
). Taken together, these results indicate that the
combination of silver and gold nanoparticles with NO may find important appli-
cations in agriculture. However, so far, this strategy has not been used, and it opens
new perspectives in this domain.
9.3.7.5 Graphitic Carbon Nanomaterials
Fullerenes, carbon nanotubes, and graphene represent a class of graphitic carbon
nanomaterials with 0D, 1D, and 2D structure and no bulk counterpart. Their unique
structure gives rise to special properties (Gogos et al.
2012
).
9.3.7.6 Carbon Nanotubes
It was demonstrated that carbon nanotubes (CNTs) are able to penetrate thick seed
coats and support water uptake inside tomato seeds, thus affecting their germination
and growth rates. This effect was explained by assuming that the activated process
of water uptake could be responsible for significantly faster germination rates and
higher biomass production observed for plants that were exposed to CNTs
(Khodakovskaya et al.
2009
). CNTs enhanced root elongation in onion and cucum-
ber, and nanotube sheets were formed by both functionalized CNTs and CNTs on
cucumber root surfaces, due to their interaction with the root surface, but not
entering into the roots. No effect on cabbage and carrot was found, but root
elongation in lettuce was inhibited by CNTs. Tomatoes were found to be most
sensitive to CNTs, with significant root length reduction (Canas et al.
2008
).
Positive effects on root growth and seed germination of six different crop species
were found (Lin and Xing
2007
; Nair et al.
2010
). No effects on zucchini plants on
seed germination and root elongation were observed, but a decrease in the biomass
of plants occurred with a long period of exposition (Stampoulis et al.
2009
). The
ability of carbon nanomaterials to penetrate cell walls and cell membranes of intact
plant cells from
Nicotiana tabacum
L. (BY-2 cells) through a fluid phase endo-
cytosis was demonstrated (Samaj et al.
2004
; Liu et al.
2009b
). These results
showed that CNT can be effectively absorbed by plants, indicating the promising
uses of this approach to carry and deliver active molecules to plants. Also the CNTs
can be associated with metallic nanoparticles leading to new nanostructured mate-
rials, which can act as NO donors in diverse applications, including in agriculture
(Taladriz-Blanco et al.
2009
). By reacting CNTs@poly(allylamine hydrochloride)
with a bimetallic nanoparticle suspension, comprised of gold and silver, a
CNT@AuAg hybrid colloid material was formed and reaction with a
S
-nitrosothiol
solution (RSNO) resulted in the bond cleavage of S-N, due to the high affinity of
gold for thiols, releasing free NO (Alvarez-Puebla et al.
2005
; Taladriz-Blanco
et al.
2009
). Irradiation of a metal nitrosyl complex greatly accelerates the rate of
NO release, by functionalization of the surface of multiwalled CNT with a Ru-NO
