Establishment and multiplication of firechalice in plant tissue culture^©

Firechalice, Epilobium canum (Greene) P.H. Raven subsp. garrettii (A. Nelson) P.H. Raven, is a small and thinly branched plant that is difficult to germinate from seed. In order to increase the number of selected individuals rapidly, plant tissue culture would be the propagation method of choice. Single-node stem explants from a selected plant were examined for their ability to establish on Murashige and Skoog (MS) medium or Woody Plant Medium (WPM). Murashige and Skoog medium was found the best salt formulation particularly when supplemented with 4.4 μM benzyladenine (BA). During Stage 2, different plant growth regulators, such as BA, kinetin (Kin), 6-(γ,γ-dimethlyallylamino) purine (2iP), thidiazuron (TDZ) and meta-topolin (mT), were used in the media in different concentrations (1.1, 2.2, 4.4 or 8.8 μM). All the cytokinins tested induced the explants to form the most shoots and shoot dry weight when used at 4.4 or 8.8 μM in the medium. A concentration of 8.8 µM BA or mT were most effective for promoting shoot multiplication, with these concentrations inducing means of 13.7 or 14.1 shoots per explant, respectively. All but one cytokinin failed to affect shoot heights at the highest concentrations used, but 4.4 or 8.8 μM TDZ decreased shoot height by at least 54% compared to the control shoots. These results indicated that firechalice shoots established the best on MS medium for Stage 1 and 4.4 or 8.8 μM meta-topolin in the medium resulted in explants forming the most and largest shoots during Stage 2.