Protocols for in vitro mass multiplication and analysis of medicinally important phenolics of a salep orchid, Satyrium nepalense D.Don (“Salam Mishri”)

Abstract

Satyrium nepalense is a rare and threatened medicinal orchid, populations of which in its native habitats are dwindling because of indiscriminate collections and habitat destruction, thus necessitating the development of methods for its in situ and ex situ conservation. Because of non-endospermous nature of the seeds and the immature embryos at seed dispersal stage, orchids cannot be seed-propagated as other plants. Micropropagation, using plant tissue culture techniques, offers an effective method for the multiplication of orchids. In this chapter, a five-step efficient reproducible protocol for large-scale in vitro multiplication of Satyrium nepalense is described. The first step involves asymbiotic germination of seeds isolated from immature green pods and cultured on Mitra’s medium (M) gelled with 0.8% agar and supplemented with 2% sucrose and 1% peptone (hereafter referred to as basal medium, BM). On this medium, seeds start germinating after a week of culture. Protocorms developed from the seeds are sub-cultured on BM fortified with 4 μM kinetin (Kn) after 8 weeks, for shoot differentiation and multiplication. The shoots developed on Kn-supplemented medium are transferred to BM alone for their elongation for the same period. The elongated shoots are transferred to the rooting medium, comprising BM supplemented with 0.5 or 1.0 μM indole-3-butyric acid, for further 8 weeks. The regenerated plantlets are transferred to a potting mix of sand and vermiculite (1:1) for acclimatization. The tubers and leaves excised from both in vitro- developed plants and those from their native habitats are analyzed and compared for the contents and concentration of medicinally important phenolics using high-performance liquid chromatography (HPLC), details of which are provided in this chapter.