Micropropagation of Romulea sabulosa Schltr. ex Beg. - A potential ornamental plant

Romulea sabulosa Schltr. ex Beg. is an endemic, attractive and rare flowering species in South Africa with horticultural potential. There is a great need to develop in vitro propagation techniques for this species for the purpose of conservation and commercialization. In this regard, the suitability of the intact seeds and embryos as explants was examined. Excised mature zygotic embryos were selected as the explant source due to a low percentage of seed germination (4.5%). Excised embryos were placed on Murashige and Skoog (MS) media supplemented with different concentrations of kinetin and 2,4-dichlorophenoxyacetic acid (2,4-D). Shoot clusters developed on MS medium supplemented with kinetin without 2,4-D. Multiplication was best on a MS medium supplemented with 2.5 μM mTR [6-(3-hydroxybenzylamino)-9-β-d-ribofuranosylpurine]. Shoots were multiplied from selected explants on a MS medium with 23.2 μM kinetin and were then used for corm induction experiments. Shoots were placed on MS media supplemented with 3, 6, or 9% sucrose, 5 mg l−1 activated charcoal or 23.2 μM kinetin. Corm formation was observed for all treatments placed at 10, 15, and 20 °C. Corm induction was significantly higher at 10 and 20 °C. The heaviest corms were produced at 15 °C on a MS medium supplemented with 6% sucrose. In some cases multiple corms formed from a single shoot. The findings of this study will assist in propagating R. sabulosa for commercial and conservation purposes.

► No literature on the propagation of the rare and attractive Romulea sabulosa.
► Selection of excised embryos as explant source due to low percentage seed germination.
► Shoots formed in vitro from embryos multiplied best on medium with 2.5 μM meta-topolin riboside (mTR).
► Viable corms produced in vitro at 10 °C.