The International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.
This award will support a twenty-two-month research fellowship by Dr. Asaph Cousins to work with Dr. Susanne von Caemmerer at the Australian National University in Canberra.
Atmospheric carbon dioxide (CO2) isotope analysis is an important tool for monitoring changes in the physiological processes controlling global exchange of CO2 and net primary productivity (NPP) of terrestrial plant communities. Generally, photosynthesis and respiration have very contrasting effects on the isotope signature of atmospheric CO2.
However, a detailed understanding of the steps responsible for CO2 isotope discrimination is needed to accurately distinguish between the processes controlling global CO2 exchange. Carbonic anhydrase (CA) regulates C4 photosynthesis and has been implicated in the isotopic discrimination of atmospheric CO2. The proposed research would utilize gas exchange and carbon/oxygen isotope measurements to study the influence of CA on the discrimination of CO2 during C4 photosynthesis in response to global climate change (i.e., water stress and elevated CO2).
This research will provide insight into the C4 photosynthetic reactions that directly affect the isotopic composition of atmospheric CO2. A better understanding of the enzymatic reactions and the leaf level gas exchange influencing the atmospheric CO2 isotope composition will allow for the development of more accurate models of current and future climatic conditions. This information will be far-reaching, further enhancing our understanding of the role of C4 plants in global gas exchange and NPP. Dr.von Caemmerer is one of the foremost experts in plant physiology and C4 photosynthesis.
