Actions for ex situ conservation of Gloriosa superba L. - an endangered ornamental cum medicinal plant

Abstract

Factors affecting in vitro propagation and microtuberization were evaluated for Gloriosa superba L., an endangered ornamental cum medicinal plant having limited reproductive capacity. Surface sterilization of tuber explants with 0.1% mercuric chloride (HgCl2) for 5 min eliminated the contamination effectively with highest survival rate. Among the various combinations used, Murashige and Skoog (MS) medium with 2.0 mg L−1 6-benzylaminopurine (BAP) + 0.5 mg L−1 α-naphthalene acetic acid (NAA) containing 3% sucrose with 16-h photoperiod exhibited the greatest in vitro tuberization (3.2) with the highest shoot regeneration frequency (90%). The longest tuber regeneration occurred on MS media containing 4% sucrose. Transfer of in vitro-regenerated shoots to half-strength MS medium with 1.0 mg L−1 indole-3-butyric acid (IBA) + 0.5 mg L−1 NAA showed maximum root induction (66.6%). The in vitro-grown plantlets were successfully acclimatized and transplanted to sterilized soil and sand mixture (3:1) in the glasshouse with 70% survival. The colchicine content was determined in the tubers of ex vitro plants by HPLC using the same retention time (1.5 min) as that of the standard colchicine. This revealed that the micropropagation protocol developed by us for rapid mass production could be used as raw material for colchicine extraction and provides a basis for germplasm conservation and genetic improvement of G. superba.