In vitro propagation of African violet: A review

African violet (Saintpaulia ionantha H. Wendl.) (Gesneriaceae) is a popular ornamental pot plant that is easy to culture ex vitro and in vitro relative to other herbaceous ornamentals. This quality makes it an ideal system for in vitro regeneration experiments. This review summarizes the studies that have been conducted on the in vitro culture and micropropagation of this plant. Although shoot regeneration from internodes, floral buds, anthers and protoplasts has been achieved, leaf blades and petioles have been a popular source tissue for regeneration. An effective and reproducible protocol for the direct induction of shoots, without the formation of any intermediary callus, involves the use of a cytokinin like BA or kinetin, usually in combination with an auxin like NAA, both within a concentration range of 0.1 to 1 mg/L, and on a Murashige and Skoog basal medium. Shoots can form in both light and darkness, but most effectively in the light, and rooting can be induced from shoots, even in the absence of an auxin, although a low concentration (0.1-0.5 mg/L) of NAA or IAA is recommended. African violets acclimatize easily, even in a simple soil-based substrate, and can flower within 4 months of transfer to ex vitro conditions. These protocols, including somatic embryogenesis and cryopreservation, may also benefit the in vitro culture and conservation of wild species of Saintpaulia.