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Elevated CO2 and Surgarcane
Reference
De Souza, A.P., Gaspar, M., da Silva, E.A., Ulian, E.C., Waclawovsky, A.J., Nishiyama Jr., M.Y., dos Santos, R.V., Teixeira, M.M., Souza, G.M. and Buckeridge, M.S. 2008. Elevated CO2 increases photosynthesis, biomass and productivity, and modifies gene expression in sugarcane. Plant, Cell and Environment 31: 1116-1127.

What was done
The authors grew sugarcane (Saccharum officinarum L.) in pots within open-top chambers maintained at either ambient (~370 ppm) or elevated (~720 ppm) atmospheric CO2 concentrations in the field under natural conditions -- except for standard fertilizer applications and for water being maintained at such a level that "no symptoms of water stress of any kind" were observed during the experiment -- at Sao Paulo, Brazil, over a period of 50 weeks, during which time, and at the end of the season, various plant physiological parameters and properties were measured.

What was learned
De Souza et al. report that, at the end of the season, the plants grown in the elevated CO2 chambers exhibited "an increase of about 30% in photosynthesis and 17% in height, and accumulated 40% more biomass in comparison with the plants grown at ambient CO2," and that the CO2-enriched plants "also had lower stomatal conductance and transpiration rates (-37 and -32%, respectively), and higher water-use efficiency (c.a. 62%)." What is more, they report that the sucrose concentration in the sugarcane leaves rose from 2.18% in the ambient-treatment plants to 2.82% in the CO2-enriched plants, for a CO2-induced increase of 29%. In addition, they found there was "a differential expression of 36 genes on the leaves (14 repressed and 22 induced) by elevated CO2," the latter of which were "mainly related to photosynthesis and development."

What it means
The ongoing rise in the air's CO2 concentration appears destined to "bring out the best" in sugarcane, as it similarly does for almost all of earth's plants. See also, in this regard, the thousands of photosynthetic and growth responses that have been observed in a host of other plants in the Plant Growth Data section of our website. Last of all, the authors say their results "open the way to possible strategies for future technologies that may improve sugarcane," and, we might add, many other important food crops, helping them to take utmost advantage of the beneficent consequences of the upward-trending atmospheric CO2 concentration.

Reviewed 10 September 2008