Efficient In Vitro Propagation Protocol of Swertia chirayita (Roxb. ex Fleming) Karsten: A Critically Endangered Medicinal Plant

Abstract

Leaf explants of critically endangered medicinal plant Swertia chirayita were cultured in Murashige and Skoog medium fortified with various concentrations of 2,4-Diclorophenoxyacetic acid (2,4-D), 6-Benzylaminopurine (BAP) and Gibberalic acid (GA3). The best callus induction was obtained in 2,4-D (15.0 µM) after 60 days of culture period. After 30 days of first subculture, maximum 32 microshoots were formed in a lump of callus in combination of BAP (10.0 µM) with GA3 (5.0 µM). On the other hand maximum 25 microshoots were formed from a lump of callus in BAP (5.0 µM) used alone. The multiple shoots developed in combination of BAP with GA3 were found poor/thin in comparison to BAP alone. Therefore, the further subculture was conducted in BAP (5.0 µM) and approximately 210 microshoots per lump of callus were obtained within 3–4 months of culture. Root induction was observed in all microshoots cultured in various concentrations of auxins (Indole-3-butyric acid, IBA and Indole-3-acetic acid, IAA) after 45 days of culture, however, the higher mean number of roots (50) per microshoot were formed in IBA (5.0 µM). After a month, well rooted plantlets were successfully transplanted and established (58.70%) in mixture of soil, sand and FYM (2:1:1) under partially shade (75% agro shade net) condition in nursery at Pothibasa (2200 m a.s.l.).