According to preliminary findings of a new study -- being released this week in Hawaii during Plant Biology 2003, the annual meeting of the American Society of Plant Biologists -- photosynthesis of maize on average increased by 10 percent under projected carbon dioxide conditions in the year 2050.
"Carbon dioxide in isolation is good news for the farmers, but unfortunately such conditions won't be in isolation from other factors, so it isn't known how significant these findings may be," said Stephen P. Long, a professor of plant biology and crop sciences.
Long is a lead researcher of SoyFACE (Free Air Concentration Enrichment), a long-term project and the only open-air experiment in the world looking at the effect of future levels of ozone and carbon dioxide gases on agricultural crops.
The corn photosynthesis findings are being exhibited by Andrew Leakey, a Fulbright scholar from Scotland who is conducting research in the SoyFACE fields with Long and with Carl Bernacchi and Donald Ort, both professors of plant biology at Illinois and scientists with the USDA/Agricultural Research Service.
Corn is among the 1 percent of plants that use the carbon-dioxide efficient photosynthesis system known as C4. Scientists had theorized that C4 plants would not respond to more carbon dioxide in the air, because the gas is internally concentrated by the leaf essentially a fuel-injected photosynthesis, Leakey said.
However, Leakey found that in a carbon dioxide concentration of 550 parts per million, carbon fixation in the leaves indeed rose in association with greater intercellular carbon dioxide and enhanced water use efficiency.