Micropropagation of the rare Eucrosia stricklandii (Amaryllidaceae) by twin-scaling and shake liquid culture

Abstract

SummaryBulbs of E. stricklandii were introduced into in vitro culture by the twin-scaling technique. Different Murashige and Skoog (MS) media supplemented with 0.5% w/v activated charcoal, naphthaleneacetic acid (NAA)/benzyladenine (BA) 0.54/4.44 μM or NAA/Thidiazuron (TDZ) 0.54/0.45 μM were used for shoot induction. Media with different combinations of 2,4-dichlorphenoxyacetic acid (2,4-D) and BA were tested during the secondary multiplication. The shoots obtained in the multiplication step were then transferred to a liquid medium with different sucrose concentrations (from 0.088 to 0.351 M) to increase biomass. Shoot bulbing was induced in 0.263.M sucrose semi-solid medium without growth regulators. Several media containing different concentrations of NAA (ranging from 0 to 5.37 μM) combined with various sucrose concentrations (from 0.044 to 0.263 M) were also tested for root induction and the bulblets were finally transplanted to soil. The best induction of shoots was obtained in the media with activated charcoal or with TDZ, but those treated with activated charcoal showed a better regeneration rate and the shoots were better formed. The best development of new shoots was obtained in the medium containing 0.45 and 4.44 μM of 2,4-D and BA, respectively. 0.175–0.263 M sucrose in the liquid medium appeared to be the most appropriate condition for increase in biomass. Rooting was promoted by low NAA concentrations (0.537–1.343 μM), and 0.175 M sucrose was the best treatment for root development.