Desiccation and Rehydration Experiments on Leaves of 43 Pteridophyte Species

Abstract

We conducted desiccation and rehydration experiments on the detached leaves of 43 pteridophyte species to assess the variability of drought adaptation strategies among pteridophytes. We found complete grades of desiccation responses from poikilohydric to homoiohydric strategies and within the latter category from mesomorphism to xeromorphism. These results suggest that pteridophytes have repeatedly evolved a wide variety of drought adaptation strategies (poikilohydry and xeromorphism at least 12 and 6 times, respectively) that are not adequately described by a simple distinction between homoiohydry and poikilohydry.