In vitro propagation of Eucomis L'Herit species -: plants with medicinal and horticultural potential

Eucomis (Family Hyacinthaceae) are deciduous geophytes with long, narrow leaves and erect, densely packed flower spikes. The bulbs are greatly valued in traditional medicine for the treatment of a variety of ailments, and are thus heavily harvested for trade in South Africa's traditional herbal markets. Eucomis species propagate relatively slowly from offsets and seed, and this, together with their over-utilisation ethnopharmacologically, has led to their threatened status. The in vitro propagation of the genus Eucomis was investigated to optimise this technique for the bulk production of plants for commercial and conservation purposes. Multiple shoot production was initiated from leaf explants, in all species studied. A Murashige and Skoog (MS) medium, supplemented with 100 mg l(-1) myo-inositol, 20 g l(-1) sucrose, and solidified with 2 g l(-1) Gelrite(R) was used. The optimal hormone combination for shoot initiation in the majority of species was 1 mg l(-1) NAA and 1 mg l(-1) BA. Optimal root initiation was demonstrated on media supplemented with 1 mg l(-1) IAA, IBA or NAA, depending on species. A continuous culture system using this protocol produced 25-30 plantlets per culture bottle, with 10-25 specimens per bottle available for acclimatisation. To maximise plantlet survival, different support media used during the acclimatisation process were necessary. Certain species responded best on a vermiculite medium, while perlite (which holds less water) was necessary for the optimal survival rate of other species. Acclimatised plantlets were repotted in a sand: soil mix (1:1).