Absorption de l'eau atmosphérique par la partie aérienne d'un chaméphyte de la Tunisie présaharienne : l’Anthyllis henoniana (Fabaceae)

Abstract

Measurements of predawn water potential made in the presaharian Tunisia (Médenine) on A. henoniana suggest that this species is able to absorb directly atmospheric water through its leaves and (or) stems. Measurements of water potential were also made on several plants in controlled conditions. Cross sections of stems of various ages and of leaves were examined. There was a good correlation between the thickness of the cortical parenchymatous tissue in leaves and young stems and the ability of a plant to maintain a less negative water potential in conditions of high atmospheric humidity. The water is apparently taken up by the vascular system. This ability would allow A. henoniana to benefit from the many dew days observed in its area of distribution and would improve its water balance. Key words: Anthyllis henoniana, dew, water potential, water absorption, water balance.