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The Impacts of Elevated CO2 on Potato Biomass and Quality
Kumari, S., and Agrawal, M. 2014. Growth, yield and quality attributes of a tropical potato variety (Solanum tuberosum L. cv. Kufri chandramukhi) under ambient and elevated carbon dioxide and ozone and their interactions. Ecotoxicology and Environmental Safety 101: 146-156.

As the air's CO2 concentration continues to rise, the growth and development of most plants tend to do better than they did under the atmosphere's prior composition. And in this regard, the two most important plant characteristics, about which most people in the food industry are typically concerned, are crop yield and nutrition, which is especially the case in India with respect to the tropical potato variety Solanum tuberosum L. cv Kufri chadramukhi.

What was done
As described by Kumari and Agrawal, well watered and fertilized S. tuberosum plants were grown from hand-sown tubers to maturity (90 days) out-of-doors at the Botanical Garden of Banaras Hindu University, Varanasi, India, in open-top chambers, after which the new tubers produced were harvested, weighed and tested for various aspects of quality.

What was learned
For the 96% increase in the air's CO2 content employed in their study, the two researchers determined that (1) new potato tuber biomass was 49% greater in the CO2-enriched treatment, that (2) both starch and soluble sugar contents were higher in the high-CO2 air, that (3) reducing sugar content was lowest in the CO2-enriched air, that (4) protein, amino acid and Ca, K, Zn and Fe concentrations were also lower by 15%, 25%, 19%, 20%, 2% and 25%, respectively, and that (5) "elevated CO2 protected the leaves from ozone injury."

What it means
As for the significance of these findings, the two researchers note that (1) "high dry matter content improves texture and crispness of the fried products, prevents excessive fat absorption in frying, and reduces the susceptibility to black spot as well as the risk of sogginess," citing Storey and Davies (1992), that (2) "the decline in reducing sugars found in this study resulting from elevated CO2 is beneficial to potato growers as high reducing sugar content is responsible for producing overly dark colors when tubers are fried in oil at high temperatures ... due to the Maillard browning reaction, which generates acrylamide, a known carcinogen," citing Mottram et al. (2002), and that (3) although protein, amino acid and some element concentrations were lower in the CO2-enriched treatment - by between 2 and 25% each - the 49% increase in total tuber biomass more than made up for these reductions in terms of the total amount of each substance harvested.

Mottram, D.S., Wedzicha, B.L. and Dodson, A.T. 2002. Food chemistry: acrylamide is formed in the Maillard reaction. Nature 419: 448-449.

Storey, R.M.J. and Davies, H.V. 1992. Tuber quality. In: Harris, P.M. (Ed.). The Potato Crop: The Scientific Basis for Improvement. Chapman & Hall, London, United Kingdom, pp. 507-522.

Reviewed 4 June 2014