Water relations between two perennial species in the steppes of southern Tunisia

Abstract

In Tunisia, the rehabilitation of overgrazed and degraded rangelands is being attempted through the reintroduction of various native perennial plant species. We studied plant-water relations in two of the leading candidate species, Seriphidium incultum (syn: Artemisia herba-alba) and Anthyllis henoniana, under conditions of water stress. Anthyllis was found to be adapted to water stress through rapid water uptake ability and a deep root system allowing access to water reserves lying deep in the soil. In contrast, Seriphidium has adapted to drought by tolerating very severe desiccation of its above-ground parts. Moreover, Seriphidium individuals consist of several hydrologically independent subunits, with the result that one part of the plant can die without damaging the rest of the plant. Relationships between xylem potential in the two species and soil water potential are also discussed. © 1994 Academic Press Limited.