Differences in the contents of total sugars, reducing sugars, starch and sucrose in embryogenic and non-embryogenic calli from Medicago arborea L

The total sugars, reducing sugars, starch and sucrose in embryogenic and non-embryogenic calli from explants (cotyledons, petioles, hypocotyls and leaves) obtained from Medicago arborea L. seedlings were evaluated. Total sugars were the major components in the calli and no significant differences between embryogenic and non-embryogenic calli were observed. In contrast, important differences between the embryogenic and non-embryogenic calli were observed for reducing sugars, the highest levels being observed in embryogenic calli. The highest starch levels were found in non-embryogenic calli developed in MS medium. During the development of somatic embryogenesis very low starch levels in the callus were found. During the first months of culture, no significant differences in the sucrose content were found between calli that produced embryos and those that did not. The most important differences in sucrose were seen between calli transferred to medium F0, which had the greatest embryogenic capacity, and those transferred to medium F6, which inhibited embryogenesis. In the latter case, an increase in sucrose was observed.