Adaptative anatomical characteristics of grapevine leaf in the south of Tunisia

Abstract

The adaptation qualities of local (Razegui, Asli) and introduced (Cardinal) grapevine cultivars were evaluated through an experimental test carried out in the Tunisian Sahara (Rjim-Mâatoug), characterized by severe environmental conditions (temperature, light intensity, sirocco and salinity). These adaptation qualities were evaluated on an anatomical and ultrastructural scale.

Thus, the histological study showed a significant difference in vine leaf blade thickeness between the north and the south, in Cardinal cultivar. The Scanning Electron Microscope results showed a remarkable difference in the leaf epidermic cell shapes between the north and the south-cultivated varieties. We think that this difference is due to abundant epicuticular wax deposits observed as irregular crystalloid plates which are definitely more abundant in the northern leaf samples than in the southern. In parallele, the transverse leaf blade section showed thicker « cuticle and outer epidermal cell wall » in the southern leaf samples than in the northern. Besides, the transmission microscopy observations confirmed the thickening of the abaxial epidermis surface, which is mainly attributed to the cell wall simultaneously with a wax accumulation across the cuticule, in the Sahara.