CLONAL PROPAGATION OF LIATRIS PYCNOSTACHYA MICHX BY IN VITRO CULTURE OF AXILLARY BUDS

Abstract

A method is described for obtaining explants free of bacterial contamination and for clonal propagation by in vitro culture of liatris axillary buds. Axillary bud growth was stimulated by removal of the shoot tips of greenhouse grown stock plants. Prior to using this approach, extreme bacterial contamination occured when explants were taken from stock plants that had not been decapitated. However, these axillary buds (0.3-0.5 cm long) were successfully established free of bacterial contamination when excised, surface disinfested and cultured on Murashige & Skoog (MS) medium supplemented with various levels of benzyladenine (BA) or kinetin and gibberellic acid (GA3). The highest number of leaves and greatest shoot length were produced by buds cultured on a medium supplemented with 1.0 mg/l BA plus 1.5 mg/l GA3. Shoot number was increased on medium containing 1.0 or 2.0 mg/l BA plus 0.5 mg/l GA3. Kinetin significantly increased the leaf number of the buds but there was no effect of kinetin on the shoot length or number. Shoots formed roots in a medium supplemented with 3 mg/l indole-3-butyric acid (IBA) plus 9 mg/l GA3. The plantlets were transferred to vermiculite and acclimatized successfully under intermittent mist in a greenhouse.