In vitro propagation via organogenesis and embryogenesis of Cyrtanthus mackenii: a valuable threatened medicinal plant

Efficient and simple, organogenesis (direct and indirect) and somatic embryogenesis (cell suspension) systems were developed for in vitro propagation of Cyrtanthus mackenii, a valuable economic plant from leaf explants cultured on Murashige and Skoog (MS) medium supplemented with various concentrations and combinations of sucrose, plant growth regulators (PGRs), glutamine, phloroglucinol (PG) and 6-(2-hydroxy-3-methylbenzylamino) purine (PI55). MS medium solidified with 8 g L-1 agar (MSS) containing 40 g L-1 sucrose, 10 A mu M picloram, 2.5 A mu M benzyladenine (BA) and 20 A mu M glutamine produced a higher number of shoots from white nodular callus. This was however, not significantly different to direct shoot regeneration on media containing 10 A mu M picloram, 2.5 A mu M BA and a reduced concentration of sucrose and glutamine. The regenerated shoots were rooted best with MSS medium incorporating 10 A mu M PG. The number of somatic embryos (SEs) were significantly higher using liquid MS medium containing 30 g L-1 sucrose, 0.5 A mu M picloram, 1 A mu M thidiazuron or BA and 3 A mu M glutamine or gibberellic acid. The embryos were germinated in PGR-free MSS medium. All plantlets were successfully acclimatized in the greenhouse. Histological studies confirmed the different developmental stages and bipolar structure of SE. The organogenesis and somatic embryogenesis protocols provides a system for large scale propagation and germplasm conservation. Developed protocols can be used for clonal production and pharmacological and genetic transformation studies.