Large scale in vitro propagation of Anoectochilus roxburghii for commercial application: Pharmaceutically important and ornamental plant

Abstract

Anoectochilus roxburghii (Orchidaceae family) is an important medicinal and ornamental plant which is in extinct condition because of the over-collected and the loss of its suitable habitats. Several protocols for A. roxburghii micropropagation have been tested but none has provided an effective method for large-scale micropropagation. The study investigates an improved and efficient propagation method including shoots generation and formation, shoot proliferation, inducing root and acclimatization. The nodal segments cut from field-grown plants were adopted as explants. Half-strength Murashige and Skoog (MS) medium supplemented with 1.5mgl−1 6-benzyladenine (BA) was proved to be the optimal medium for shoots generation and induction, on which, the shoot formation rate was 91.67%. Shoots were inoculated on such four media as half-strength MS, MS, Vacin and Went (VW), and Gamborg (B5), containing various concentrations and combinations of the cytokinins BA, 0.5–4.0mgl−1, kinetin (Kn), 0.1–2.0mgl−1, and the auxin 1-α-naphthaleneacetic acid (NAA), 0–0.5mgl−1, to select the optimal conditions for shoot growth and proliferation. Among those, the highest proliferation rate was 4.33, which was obtained on half-strength MS medium fortified with 3.0mgl−1 BA, 1.0mgl−1 Kn, 0.5mgl−1 NAA and additives. The half-strength MS medium supplemented with 0.6mgl−1 NAA, 0.3mgl−1 indole-3-butyric acid (IBA) and 100mgl−1 banana mashes turned out to be best medium for in vitro rooting, which has a inducing root rate of 93.33%. The rooted plantlets were successfully transferred into plastic cups containing a sterile sand and peat soil mixture in a ratio of 1:2, and the surface was covered with live moss. The survival rate for A. roxburghii was 90.2%. The described protocol can be efficiently used for the large-scale propagation and conservation of the germplasm of this endangered medicinal and ornamental plant.