A comparative analysis of C3 and C4 photosynthesis under dynamic light conditions
By 2050, human population growth is predicted to require to a 100-110% rise in global food production, and since traditional targets for crop advancement are falling behind rising demand, improving photosynthesis to increase crop yield has become a major global effort. The response of plants to changes in light intensity has been identified as a source of inefficiency for photosynthesis, as in the dynamic environments of the open field, where crop canopies are subject to constantly changing light intensity, lags in photosynthetic responses can amount to up to a 40% loss in daily carbon assimilation. Although remarkable progress has been made, the vast majority of the work on dynamic light photosynthesis has been conducted in C3 species, despite the undeniable global importance of C4 crops to global food supplies. The benefits of the C4 carbon concentrating mechanism under steady state conditions are well-established, but it is less clear how the C4 pathway affects the dynamic light response. This thesis employs a comparison between phylogenetically linked C3 and C4 species across three different genera to compare C3 and C4 photosynthesis under non-steady state conditions. The findings presented in this thesis enhance our understanding of the effects of the biochemical and anatomical features of the C4 pathway on photosynthetic responses to dynamic light, and on the potential impact of specific engineering strategies for the improvement of photosynthesis in C4 species.