Net photosynthesis and leaf water potential of buffel grass (Cenchrus ciliaris L.) accessions, growing in the arid zone of Tunisia.

Studies of the functional mechanisms and behavior of plants are needed, in order to use phytogenetic resources in the rehabilitation and restoration programs of degraded ecosystems. Indeed, given the scale of disturbance affecting the arid and saharan ecosystems of Tunisia, attempts to improve and restore the ecological balance are deemed necessary (Aronson et al., 1993). However, the success of such operations can only be guaranteed by the use of native species (Chaieb et al., 1992; Ourcival et al., 1994). Several studies have been carried out in the Tunisian arid zones on the water use dynamics of various perennial species (Floret & Pontanier, 1978; Le Houerou, 1984) such as Cenchrus ciliaris, Stipa lagascae, Plantago albicans, Argyrolobium uniflorum. In addition to their pastoral qualities, these species are suitable for sand stabilization and combating desertification (Le Houerou, 1995). Furthermore, they improve the soil water balance by reducing soil aridity (Floret & Pontanier, 1984). Our contribution towards the process of even partial restoration of the ecological balance in the North African environment in general and in Tunisia in particular, consists an ecophysiological study of one key species of Tunisian arid zones. Cenchrus ciliaris L. is a perennial buffel grass and C4 plant, in the grass family (Poaceae), invading arid tropical habitats around the globe. It is one of the candidate species for ecological restoration of deNet photosynthesis and leaf water potential of buffel grass (Cenchrus ciliaris L.) accessions, growing in the arid zone of Tunisia