Impact of changing atmospheric CO2 concentrations over the Phanerozoic on stomatal parameters of vascular land plants

A novel and multi-disciplinary subject involving the relationships between changes in atmospheric CO2 concentration throughout the geological history and features of plant anatomy is reviewed. Particular attention will be giv en to stomatal parameters (stomatal density and stomatal index) which are r ecorded at a cellular level in fossil plants and the relationships of these observable parameters to earth life history and global environmental chang e. Trends of atmospheric CO2 concentrations during the Phanerozoic period a re briefly introduced and recent conceptual advances in understanding the c ausal mechanisms for changes in stomatal parameters of land vascular plants are considered. In addition, some of the inherent problems and limitations of this kind of work are discussed and future research directions are pres ented.