Quantifying C18OO discrimination and Co2 diffusion in C3 and C4 leaves

The oxygen isotope composition of atmospheric CO2 is an important signal that helps distinguish between ecosystem photosynthesis and respiration. Plants with the C4 photosynthetic pathway, like sugarcane and tropical pasture grasses, play a major role in Australian agriculture and natural ecosystems. We will test key assumptions required for modelling oxygen isotope discrimination during C4 photosynthesis at the leaf and canopy scale. This will provide new insights into the regulation of C4 photosynthesis needed for C4 crop improvement and provide parameter constraints for global isotope mass balance models.