Plant regeneration in the root callus culture of Betula pendula Roth

Callus proliferation and adventitious bud regeneration were induced in root segments of Be­tula pendula Roth on a mod. ACM medium supplemented with 2.2 - 8.9 µMBA. Regenerated adventi­ tious buds elongated when transferred to a mod. ACM medium containing 2.2 µM BA. Adventitious shoots multiplied by an axillary bud culture were successfully rooted on the same medium containing 1.0 µM IBA. Within one callus culture, one of the adventitious shoots was morphologically different from the mother plant as well as from other regenerated shoots. Cytogenetic analysis showed a higher mitotic activity in the root-tip cells of the altered variant while no changes in the chromosome number were no­ ticed. Protein content was significantly higher in the altered variant in comparison with the mother plant and other sister-regenerants, though the electrophoretic banding pattern was rather similar.