ORGANOGENESIS AND SOMATIC EMBRYOGENESIS OF BEAUCARNEA INERMIS (ASPARAGACEAE), A THREATENED SPECIES FROM NORTHEASTERN MEXICO

Abstract

Somatic embryogenesis and organogenesis were induced through five explant types of Beaucarnea inermis plants 90 days old and generated from in vitro germination. For somatic embryogenesis, B5 medium was used in basal leaf segment and callus derived from stem apex and 2.2 and 3.6 embryos were generated, respectively; both in the presence of 0.5 mg L-1 kinetin + 2 mg L-1 2,4-dichlorophenoxyacetic acid. In stem apex a mean of 6.8 embryos were registered with 0.5 mg L-1 kinetin + 4 mg L-1 2,4-dichlorophenoxyacetic acid. The combination of light and 2,4-dichlorophenoxyacetic acid in callus induced root formation. For somatic organogenesis, MS medium was used in basal leaf segment and 2.8 adventitious shoots were generated in the presence of 6 mg L-1 benzyladenine + 0.5 mg L-1 naphthalen-l-acetic acid. The callus and stem apex generated 11.3 and 15.7 shoots, respectively; both in the presence of 2 mg L-1 benzyladenine. Somatic embryos germinated and developed into plantlets in basal MS media. In vitro root formation in individualized shoots incremented when 1 mg L-1 of indo1-3 butyric acid was added to the medium. One hundred percent survivorship was registered 90 days after transplanted under greenhouse conditions. Both propagation methods produced the typical stem thickening. In this study, an efficient micropropagation protocol was established as an alternative to produce ornamental plants and indirectly as a way to reduce the exploitation of wild populations.