Plant carbon metabolism and climate change: elevated CO2 and temperature impacts on photosynthesis, photorespiration and respiration

Plant carbon metabolism is impacted by rising CO2 concentrations and temperatures, but also feeds back onto the climate system to help determine the trajectory of future climate change. Here we review how photosynthesis, photorespiration and respiration are affected by increasing atmospheric CO2 concentrations and climate warming, both separately and in combination. We also compile data from the literature on plants grown at multiple temperatures, focusing on net CO2 assimilation rates and leaf dark respiration rates measured at the growth temperature (A(growth) and R-growth, respectively). Our analyses show that the ratio of A(growth) to R-growth is generally homeostatic across a wide range of species and growth temperatures, and that species that have reduced A(growth) at higher growth temperatures also tend to have reduced R-growth, while species that show stimulations in A(growth) under warming tend to have higher R-growth in the hotter environment. These results highlight the need to study these physiological processes together to better predict how vegetation carbon metabolism will respond to climate change.