Adaptabilité des espèces du genreAtriplexaux conditions de salinité et d'aridité

Plants have had to cope with periodic, unpredictable environmental stresses during growth and development. Surviving such stresses over a long evolutionary scale led plants to acquire mechanisms allowing them to sensitively perceive stresses and regulate their physiology accordingly. In the arid and semi arid regions of the world, shrubs surviving in saline soils have been the subject of considerable research. They have been evaluated as alternative sources of forage for livestock. Thus, Rehabilitation of rangelands with shrubs can add to feed resources and stop land degradation. The genusAtriplex(Chenopodiaceae) is a perennial halophyte witch is distributed all over the world and widely used in rehabilitation programs.Atriplexspp are strong candidates for cultivation because of their adaptation to the climate and soil and mainly for their nutritive value for grazing animals during the hardest periods of the year. The aim of this study is to evaluate the adaptability of two species,A. nummulariaetA. halimusto conditions of drought and salinity under controlled and field conditions. The effect of two irrigation regimes and of an increasing salinity were tested. Moreover, propagation, cutting intensities to simulate browsing, nutritive value, growth under rainfed conditions of 30 clones ofA. halimuswere studied to select some clones with both good nutritive value and abiotic stress resistance to act upon plant improvement programs for salinity and drought conditions.