Photosynthesis optimized across land plant phylogeny

Until recently, few data were available on photosynthesis and its underlying mechanistically limiting factors in plants, other than crops and model species. Currently, a new large pool of data from extant representatives of basal terrestrial plant groups is emerging, allowing exploration of how photosynthetic capacity (A_max) increases from minimum values in bryophytes to maximum in tracheophytes, which is associated to an optimization of the balance between its limiting factors. From predominant mesophyll conductance limitation (l_m) in bryophytes and lycophytes (fern allies) to stomatal conductance (l_s) and l_m colimitation in pteridophytes (ferns) and gymnosperms, a balanced colimitation by the three limitations is finally reached in angiosperms. We discuss the implications of this new knowledge for future biotechnological attempts to improve crop photosynthesis.