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Effects of Elevated CO2 on Nicotine Content and Spread of Potato Virus Y in Tobacco Plants
Matros, A., Amme, S., Kettig, B., Buck-Sorlin, G.H., Sonnewald, U. and Mock, H.-P. 2006. Growth at elevated CO2 concentrations leads to modified profiles of secondary metabolites in tobacco cv. SamsunNN and to increased resistance against infection with potato virus Y. Plant, Cell and Environment 29: 126-137.

What was done
Tobacco plants (Nicotiana tabacum L., cv. SamsunNN) were grown in 16-cm-diameter pots filled with quartz sand in controlled-climate chambers maintained at either 350 or 1000 ppm CO2 for a period of eight weeks, where they were irrigated daily with a complete nutrient solution containing either 5 or 8 mM NH4NO3. In addition, some of the plants in each treatment were mechanically infected with the potato virus Y (PVY) when they were six weeks old. At the end of the study, the plants were harvested and a number of their chemical constitutes identified and quantified.

What was learned
The authors report that "plants grown at elevated CO2 and 5 mM NH4NO3 showed a marked and significant decrease in content of nicotine in leaves as well as in roots," while at 8 mM NH4NO3 the same was found to be true of upper leaves but not of lower leaves and roots. With respect to the PVY part of the study, the six German researchers say that the "plants grown at high CO2 showed a markedly decreased spread of virus."

What it means
Keeping the story simple, Matros et al. concluded, in their words, that "tobacco plants grown under elevated CO2 show a slight decrease of nicotine contents," and that "elevated CO2 resulted in reduced spread of PVY." Both of these findings would likely be considered by most people to be beneficial, as potato virus Y is an economically important virus that infects many crops and ornamental plants throughout the world, while nicotine is nearly universally acknowledged to have significant negative impacts on human health (Topliss et al., 2002).

Topliss, J.G., Clark, A.M., Ernst, E. et al. 2002. Natural and synthetic substances related to human health. Pure and Applied Chemistry 74: 1957-1985.

Reviewed 24 May 2006