Résumé:
The induction of somaclonal variant resistant at salt stress in vitro requires a selection of resistant cell lines. For better resistance to abiotic stress, the Induction of stem and leaf callus of Solanum tuberosum L., at Spunta and Kondor variety was initiated in MS medium with 0.5 mg.l-1 ANA, and 0.5 mg.l-1 2.4-D. Their exposure to different concentrations of sodium chloride (from1 to 14 g.l-1), showed the direct effect of this stress on the texture, growth and somatic callus organogenesis. Determination of salt tolerance stress callus performed until the second generation of transplanting. The application of concentration superior to 5 g.l-1 of NaCl induces a non-organogenesis texture (friable callus, smooth and necrotic), it's the lethal concentrations. Microscopic calluses observations, followed by statistical analysis, have outlined the tolerance threshold of 4 g.l-1 in the two explants. In terms of tolerance, there is no difference between stem callus and leaf callus, but only at the level of growth, which is more favorable in stem callus. These are proving more of somatic organogenesis in the presence of salt stress. The measure of stress tolerance index shows the dominance of meristem callus on leaf callus in terms of tolerance .The Induction of somatic meristems is optimized for G4 generation in stem calluses and G3 in leaf calluses; and disappear from G6 in leaf calluses to G7 in stem calluses. The variety of factors has a significant effect on the intensity of organogenic callus.
