XVI International Botanical Congess
The Devonian Rhynie Cherts contain exceptionally well preserved plant fossils. The detailed investigation of their anatomical structures can also be used to reconstruct relevant physiological parameters. In this contribution, detailed computer-based simulations of the gaseous exchange of some early land plants are presented. This approach allows for simulating the fluxes of carbon dioxide and water vapour into and out of, as well as within the plant. The results demonstrate that the water use efficiencies of the Rhynie Chert plants were, compared to extant land plants (C3 plants), probably very high. The results are discussed within the context of a) possible adaptations to the environment including climatic conditions of the Devonian and b) constructional limitations of the plant itself.