As a result of human activities including fossil fuel combination and forest burning, the concentration of atmospheric carbon dioxide (CO2) is currently higher than in recorded history and it is rising at an unprecedented rate. CO2 is one of the several `greenhouse gases` and the rapid increase in its concentration may lead to global climatic warming. Vegetation plays a large role in the global CO2 cycle-it removes CO2 from the atmosphere in the process of photosynthesis and releases CO2 to the atmosphere in the process of respiration. Any changes in global photosynthesis or respiration will affect the rate of change of atmospheric CO2 concentration. Recent studies indicate that plant respiration may be inhibited in the short-term by increased CO2 concentration, yet virtually nothing is known of the underlying physiological mechanism(s), the duration of the response, or how widespread this phenomenon is in nature. The proposed research initiates an examination of the biochemical and physiological basis of the direct effect of CO2 on respiration using a combination of novel experimental approaches in both laboratory and natural settings. The research should significantly advance knowledge of the regulation of plant respiration by CO2. In turn, this will improve our understanding of the role of vegetation in regulating atmospheric CO2 concentration and, thus, the potential for global climate change.
