Induction of somatic embryogenesis from leaf explants of safed musli (Chlorophytum borivilianum)
Dr. Nasim Akhtar and Aklank Choudhary
Safed musli (Chlorophytum borivilianum) is an endangered medicinal plant of liliaceae along with a few other species. It has a very short life cycle (90–100 days). The root of plant is widely used as tonic and aphrodisiac and other important application in Indian system of medicine since ancient time. It contains steroidal saponin viz. neotigogenin, neon hecogenin, stigmasterol and tokorogenin. It is propagated through the fleshy tubers as seeds of plant have only 10-14% germination. Limited success in plant let regeneration from leaf discs and seedling derived calli have been reported via somatic embryogenesis and organogenesis because of heavy contamination (80- 100%) of cultures. Culture contaminations have been controlled to 20-40% level with the leaf and central root disc explants in the present study. Murashige and Skoog’s medium proved better for establishment of culture as well as induction of somatic embryogenesis. Induction of somatic embryogenesis was achieved from basal leaf portion while other explants failed to do so. An optimum of 6% sucrose in medium was required for induction and development of somatic embryos. Amongst the different auxins and cytokinins, naphthalene acetic acid alone was effective for induction of somatic embryogenesis. Other growth regulators either alone or in various combinations permutations were inhibitory for induction and development of somatic embryos. The basal leaf portion showed swelling in the first week and development of calli by bursting of leaf surface in the second week of culture initiation. Somatic embryos appeared as globular and developed to scutellar notch stage and finally as well developed scutellum, coleoptile and coleorhiza with simultaneous maturation within 5 to 6 week of culture initiation. Upon subculture of somatic embryo to fresh medium with similar levels of sucrose and NAA in both agar solidified and liquid suspension medium showed germination and converted in to normal plantlets within two weeks. Further growth of the plantlets was achieved in liquid medium with 3% sucrose and plantlets were transplanted in soil compost mix after two weeks. About 80 – 100% of normal and properly matured somatic embryos converted into plantlets and survived well following the acclimatization process.