In vitro regeneration of long spur barrenwort (Epimedium grandiflorum Morr.) from rachis explants

A system for micropropagation of Epimedium grandiflorum Morr. from rachis e xplants was developed. Explants were cultured onto Murashige and Skoog (MS) basal salts medium supplemented with (per L) 100 mg myo-inositol, 2 mg pyr idosine-HCl, 2 mg nicotinic acid, 0.40 mg thiamine-HCl, 30 g sucrose, and 2 g Phytagel. The medium also contained 2,6dichlorophenoxyacetic acid (2,4-D ) at 0.1, 0.2, or 0.25 mg/L (0.5, 0.9, or 1.1 mu M.) combined with either N -6-benzyladenine (BA) or 2-isopentenyl adenine (2ip) at 2.5, 5, or 10 mg/L (11.1, 22.2 or 44.4 mu M BA or 12.3, 24.6, or 49.2 mu M 2iP). Cultures were maintained at a 16-h photoperiod (40 mu mol/m(2)/s) and 23 +/- 2 degrees C . Callogenesis preceded shout regeneration. Callus formation increased with higher 2,4-D concentrations. The highest percent regeneration, 83% of expl ants, was obtained on 10 mg BA per L (44.4 mu M) combined with 0.25 mg 2,4- D per L (1.1 mu M). The maximum number of shoots, 15 per explant. was obtai ned from explants cultured on a medium containing 0.1 mg 2, 4 -D per L (0.4 5 mu M) combined with 2.5 mg BA per L (11.1 mu M). Maximum shoot length, 0. 4 cm, was obtained on 5 mg BA per L (22.2 mu M) combined with 0.2 mg 2,4 -D per L (0.9 mu M). To produce whole plants, shoots were separated and roote d on hormone-free medium containing 1 g activated charcoal per L. Rachises provided an excellent source of explants for Epimedium micropropagation and proved suitable for callus production.