Effet du biotope sur la diversité des caractères morphologiques des populations naturelles d’Atriplex canescens dans la région d’Oran (Lac Télamine)

Abstract

Atriplex canescens is a neophyte species native to North America. Naturally, the naturalization of xerophytic species in Algeria is an ongoing process. The species constitutes an important source of fodder for livestock. To contribute to the understanding of this species and its behavior in its biotope, which is located in a wetland, Lake Télamine, we attempted to monitor the behavior in terms of morphological variability of older individuals and young seedlings (height, diameter, basal coverage, number of branches, leaf length and width, and dry matter). The results reveal that the Atriplex canescens population is located in a very harsh climatic context, where average annual rainfall varies from year to year, with a more or less regular rainfall pattern and a pronounced drought lasting several months. The site belongs to the humid bioclimatic zone with a warm variant. Soil analysis results allowed us to distinguish a predominant texture: a silty and clayey texture with an alkaline pH, very high total limestone content, and richness in organic matter. The analyzed soils range from slightly saline to very saline given their proximity to the salt waters of Lake Télamine. Atriplex canescens is a polymorphic plant; this morphological polymorphism is very pronounced in the clumps, which have a very specific shape to Atriplex: the cushion shape. Measuring the length and width of the leaves, as well as the leaf ratio, allowed us to identify a very pronounced polymorphism from the young age of the species. The species is distinguished by its high dry matter production; the twigs are 75.59 % richer in dry matter than the leaves 37.69 %.