Agriculture Reference
In-Depth Information
Fig. 2.5 TEM images of chickpea root tissue (a) without and (b) with exposure to CNTs.
White
arrows mark
the carbon nanotubes.
Inset
in (b) shows a close-up image of a CNT within the tissue.
(c) Comparison of plants after 10 days of growth. The plants exposed to CNTs showed greater root
and shoot length as well as water uptake (Tripathi et al.
2011
). Reproduced with permission from
Springer
seeds soaked in 2.5 % nano-TiO
2
solutions under natural light illumination showed
almost 3.5 times higher vigor indices compared to seeds treated with bulk TiO
2
.Dry
weight of the plants was 47 % higher in the nano-treated seeds than the bulk-treated
seeds, and chlorophyll content increased by 28 %. These improvements are attributed
to the photocatalytic effects of nano-TiO
2
. More recently, the hypothesis was pro-
vided that nano-TiO
2
promotes photosynthesis and nitrogen metabolism within the
plant (Yang et al.
2007
). Similar photocatalytic effects have been claimed in patents.
For example, particles of partially crystalline polymers such as polyethylene, poly-
propylene, etc., mixed with semiconductor nanoparticles, such as tin oxide, indium
oxide, or indium-tin oxide (maximum diameter of 200 nm), are claimed to improve
the efficiency of sunlight utilization by plants (Caro et al.
2006
). Table
2.2
lists
patents and patent applications whose inventions fall under category 2, grouped in
terms of their nano-content.
