Somatic embryogenesis and plant regeneration in Pterocarpus marsupium Roxb

摘要

Somatic embryogenesis (SE) has been achieved from hypocotyl-derived callus culture in Pterocarpus marsupium. Ninety percent of hypocotyl explants (excised from 12-day-old in vitro germinated axenic seedlings) produced callus on Murashige and Skoog medium supplemented with 5 oM 2,4-dichlorophenoxyacetic acid and 1 oM a 6-benzyladenine (BA). Induction of SE occurred after transfer of callus clumps (200 pl 20 mg fresh mass) to MS medium supplemented with BA at 2.0 oM, where a maximum of 23.0 pl 0.88 globular stage embryos per callus clump were observed after 4 weeks of culture. Subculturing of these embryos on MS medium supplemented with 0.5 oM BA, 0.1 oM l-naphthalene acetic acid and 10 oM abscisic acid significantly enhanced the maturation of somatic embryos to early cotyledonary stage, where 21.4 pl 0.32 embryos per callus clump were recorded after 4 weeks of culture. Of 30-well developed somatic embryos, 16.6 pl 0.33 germinated and subsequently converted into plantlets on half-strength MS medium supplemented with 1.0 oM BA. The morphologically normal plantlets with well-developed roots were first transferred to 1/4-liquid MS medium for 48 h and then to pots containing autoclaved soilrite and acclimatized in a culture room. Thereafter, they were transferred to a greenhouse, where 60% of them survived.