Regeneration of plants from in vitro root segments of Holostemma annulare (Roxb.) K. Schum., a rare medicinal plant

摘要

Plant regeneration was achieved from chlorophyllous root segments derived from in vitro rooted plants of Holostemma annulare (Roxb.) K. Schum (H. adakodian R. BR. ex. Schult., Asclepiadaceae), a rare medicinal plant grown for 8-9 weeks in half-strength Murashige and Skoog (MS) medium with 0.3 mg/l indole-3-butyric acid (IBA). Up to 82% solitary shoot bud initiation with small laterals was obtained from the excised (3-4 cm) root segments implanted horizontally on MS agar medium supplemented with 0.2 mg/l benzyladenine (BA) within 2 weeks. Rapid elongation of both shoot and lateral root initials was observed upon transfer of the responded root segments to a half-strength MS medium lacking growth regulators (basal medium). The shoots attained a length of 13-14 cm with 8-9 nodes in a period of 3-4 weeks of culture in the basal medium. After 5-6 weeks incubation, the regenerated shoots having elongated roots with parental root segments were transferred to the field, and showed 80% survival after a hardening period of 4 weeks in the mist chamber. For further shoot multiplication, the rhizogenic shoot provided 8-9-fold multiplication rates in the MS medium supplemented with 0.5 mg/l BA and 0.05 mg/l alpha-naphthaleneacetic acid (NAA). [References: 21]