Adaptation au NaCl de Lycopersicon esculentum : étude comparative des cultures de cals ou de parties terminales de tiges

Abstract

In tomato (Lycopersicon esculentum Mill. cv. St-Pierre), an adaptation to 75 or 100 mM NaCl, which results in an increase in growth, is obtained after transferring on media gradually enriched in NaCl, during four generations, either terminal parts of stems (including terminal bud and last internode) or calli initiated from roots or stems. Conversely, no growth increase is obtained at the fourth generation, when the culture medium has a NaCl concentration similar to that of the preadaptation medium of calli or young plants of the three previous generations. A comparison between the growth of calli and that of young plants originating from transfer of terminal parts of the stem reveals that the latter have the best NaCl adaptative abilities. Among the factors linked to the adaptative process at the level of cell masses of calli or at the level of differentiated cells of young plants are Na and Cl content, a decrease of Cl/Na ratio, an increase of K, Ca, or soluble sugar contents, the proline synthesis, a repartition of ions or metabolites proportional to accumulated masses, and an increase of peroxidase activity in plant roots.