Establishment of an efficient in vitro propagation system for Holostemma annulare (Roxb.) K. Schum. using SH medium

Abstract

Holostemma annulare (Roxb.) K. Schum. (Asclepiadaceae) is an important medicinal herb and its root tubers are an important ingredient of the drug ‘jivanti’. Here, a more reliable procedure of in vitro propagation of the plant is discussed using SH nutrient medium formulation that facilitates the in vitro multiplication and establishment without callusing from the basal region of shoots that was prominent in the earlier protocols. Surface sterilization of the nodal explants with 10% (v/v) NaOCl for 12 minutes followed by 0.1% (w/v) HgCl2 for 8 minutes exhibited 90% shooting response. The in vitro initiated shoots subcultured to SH medium fortified with 2.0 mgl-1 BA in combination with 0.5 mgl-1 Kinetin and 1.0 mgl-1 IBA produced maximum 7.16±0.15 shoots. Better root induction of the in vitro raised shoots was noticed in SH medium augmented with 0.01 mgl-1 NAA that induced a mean number of 5.65±0.23 thin, long, white coloured roots. The plantlets were transferred to polythene bags containing river sand:garden soil (1:1) for acclimatization, further transplanted in garden soil and river sand mixture (3:1) in earthern pots in the greenhouse and subsequently to the field got established at 80% efficiency. They produced tuberous roots after 4 months of field establishment. Thus, the study standardized an improved system of in vitro propagation of H. annulare using SH medium and this protocol can be extended for long-term conservation methods such as cryoconservation and also for the in vitro production of bioactive metabolites.