247th ACS National Meeting, Dallas, Texas, March 16-20, 2014

ACS 2014

Adaptation of higher plants to changes in atmospheric carbon dioxide concentration (ENVR233)

ACS Meeting Name

Spring 2014 Dallas ACS National Meeting (March 16-20, 2014)


James Bunce


Division of Environmental Chemistry (ENVR)

Syposium/Session Title

(WED-AM) Changing Atmospheric Chemistry: Environmental Implications of Land-Air Interactions

Session Date and Time

Wednesday, March 19, 2014, 8:30 AM

Lecture ID



The concentration of carbon dioxide in earth''s atmosphere has varied greatly over geologic time, from about 3000 to 4000 parts per million by volume (ppm) when plants invaded land about 400 million years ago, to less than 200 ppm several times within the last half-million years. Such changes in concentration would have profound effects on photosynthesis and stomatal conductance of plants, which are the most obvious plant processes which respond directly to carbon dioxide concentration. Low carbon dioxide concentrations have been implicated in the evolution of C4 photosynthesis, which uses metabolic energy to concentrate carbon dioxide at the site of the first enzymatic step in the C3 photosynthesis pathway. Despite the fact that modern gymnosperms and angiosperms evolved when the carbon dioxide concentration was about 2000 ppm, there is some evidence that these higher plants are currently adapted to the lower concentrations of the more recent past. Efforts are currently underway to determine what traits would improve the adaptation of crops and other plants to projected changes in atmospheric carbon dioxide concentration. Results suggest that more subtle changes than altered properties of photosynthesis and stomatal conductance may be important.

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