Future Prospects - Genetics, Genomics and Breeding of Crop Plants - page 329

However, the rate of phytoextraction of zinc by sunflower from soils very
heavily contaminated by a toxic spill at a pyrite mine was very low and was
not a feasible option for zinc removal, although the sunflower plants were
effective in stabilizing the contaminated soil (Madejón et al. 2003).
The symbiotic relationship between sunflower and microbes can be
exploited to enhance heavy metal ion accumulation by the plant, and is
environmentally more favorable than using metal ion chelators, which run
the risk of leaching chelated metals into groundwater. Uptake of chromium
ions by sunflower roots was enhanced by inoculation of the roots with
mycorrhizal fungi (Davies et al. 2001). Similarly, inoculation of sunflower
roots with the rhizobacterium Pseudomonas putida 06909, which had been
engineered to express a synthetic metal-binding peptide, increased cadmium
binding by 40% (Wu et al. 2006). Thus, for moderately contaminated soils,
the symbiotic combination of sunflower and microbes may provide a
practical option for phytoremediation.
10.6 Outlook
In many parts of the world, especially Europe, South Asia, and Central and
South America, sunflower oil is well established as a preferred vegetable oil
for household cooking. The recent introduction of mid-oleic sunflower into
the North American market has driven demand for sunflower oil to such an
extent that producers can barely meet the demand. Mid-oleic sunflower oil
is currently considered the ideal frying oil for snack foods by the US snack
food industry, due to its favorable composition of approximately 65% oleic
acid (high frying stability and shelf life), about 22% linoleic acid (precursor
to desirable flavor components), and low saturated fatty acid content. The
resulting shortage of mid-oleic sunflower oil has made bottled sunflower
oil unavailable in supermarkets to most US consumers in recent years.
Sunflower oil as a premium oil will be challenged in future years as
soybean breeders make advances to reduce or eliminate the linolenic acid
content of soybean oil and to achieve a mid-oleic fatty acid composition
similar to sunflower, while continuing to maintain yield and other important
agronomic traits. Canola oil, with its low saturated fatty acid composition,
will likely persist as a strong competitor to sunflower oil. Despite the
continued competition from other vegetable oils, sunflower oil will continue
to maintain an image advantage as a heart-healthy vegetable oil over other
oils simply because of the visual impact of a beautiful, radiant and showy,
bright yellow flower that appealed first to Native Americans, and has now
been adopted and admired by the rest of the world for over five centuries.