Der Wasser- und Photosynthesehaushalt von Wüstenpflanzen der südalgerischen Saharal ) : I. Standorte und Versuchspflanzen

Abstract

In three parts we communicate the results of ecophysiological field investigations in the North Saharian desert around Beni Ounif, on the foot of the Sahara-Atlas. In the present first part, after a general discussion of the climatic and edaphic milieu conditions (fig. 2, 3, 4) and of the geographic and sociologic position of the vegetation, the experimental habitats and plants are characterized in particular (table 1, 2). The following species of perennial constitutional types were examined: Malacophyllous shrubs ( Ziziphus lotus, Rhus tripartita, Capparis spinosa ); nanophyllous shrubs ( Thymelaea microphylla, Tamarix gallica ); switch·shoot shrubs ( Retama retam, Ephedra alata, Zilla macroptera, Launaea arborescens, Pituranthos scoparius, Rhantherium adpressum, Randonia africana, Coronilla juncea ); switchshoot hemicryptophytes ( Juncus maritimus ); malacophyllous hemicryptophytes and geophytes ( Peganum harmala, Citrullus colocynthis, Phragmites australis ); sclerophyllous cushion hemicryptophytes (Anabasis aretioides); sclerophyllous hemicryptophytes ( Echinops spinosus, Centaurea pungens ); succulents ( Limoniastrum feei, Zygophyllum album, Frankenia thymoides ). The geographical areas demonstrate the holarctic origin of the vegetation, in which trees are absent and switchs-hoot shrubs prominent. The different con-stitution types are characterized by the dimension quotient and the anatomy of the leaves and by the structure of the root system (table 2, fig. 5-22).