The researchers have found that the process, photorespiration, is necessary for healthy plant growth and if impaired could inhibit plant growth, particularly as atmospheric carbon dioxide rises as it is globally. Their findings are published this week in the Proceedings of the National Academy of Sciences.

Over the past two hundred years, scientists have come to understand that plants are amazing biochemical factories that harness energy from sunlight to convert water and carbon dioxide into sugars that fuel the plant, while giving off oxygen.

Though elegantly simple in concept, this process, known as photosynthesis, is remarkably complex in detail. And for years, researchers have been puzzled by another process, photorespiration, which seems to have annoyingly associated with photosynthesis down the evolutionary pathway.

Photorespiration has appeared to be downright wasteful because it virtually undoes much of the work of photosynthesis by converting sugars in the plant back into carbon dioxide, water and energy.

Believing that photorespiration is a consequence of the higher levels of atmospheric carbon dioxide in long past ages, many scientists concluded that photorespiration is no longer necessary. Some have even set about to genetically engineer crop plants so that the activity of the enzyme that initiates both the light-independent reactions of photosynthesis and photorespiration would favor photosynthesis to a greater extent and minimize photorespiration.

The result, they have thought, would be more productive crop plants that make more efficient use of available resources.

But the new UC Davis study suggests that there is more to photorespiration than meets the eye and any a
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Contact: Andy Fell
ahfell@ucdavis.edu
530-752-4533
University of California - Davis
22-Jul-2004