XVI International Botanical Congess

The production and emission of isoprene by plants provides the single largest source of reduced photochemically reactive compounds to the atmosphere. It also represents a pathway for carbon loss from plants that can, under certain conditions, equal a substantial fraction of net photosynthesis. Isoprene production and emission were discovered in the 1950's, but the function of, and controls over, isoprene production are still under debate. I present evidence for a heirarchy of production controls, from genetic to biogeochemical. Phylogenetic factors appear to be the most important in regulating isoprene emissions, but, to date, too few taxa have been sampled to allow interpretation of the phylogenetic signal. I also demonstrate the role of biochemical, physiological, and ecological processes in regulating isoprene production and emission. Understanding the controls at each of these scales is essential for both studying the adaptive significance of isoprene production and for developing predictive models of isoprene emission from plants to the atmosphere.