AUXIN, CALCIUM AND SODIUM IN SOMATIC EMBRYOGENESIS OF AFRICAN VIOLET (SAINTPAULIA IONANTHA WENDL. CV. BENJAMIN)

Induction of petiole explants with thidiazuron resulted in the development of somatic embryos originating from the epidermal cells of African violet petioles.
Orientation of the petiole explants and auxin transport were found to be a crucial factor in regulation of the embryogenic response.
The current study was designed to assess the effect of thidiazuron on the induction of somatic embryogenesis and the role of ion transport in the thidiazuron-induced morphogenesis.
Incorporation of the agonists of calcium channels, (S)-Bay K8644, into the thidiazuron-medium changed the pattern of somatic embryogenesis such that an embryogenic callus formed across the tissue and subsequently embryos formed on the callus. Antagonists of calcium movement, diltiazem and verapamil, inhibited the embryogenic response.
Lidocaine, an antagonist of sodium channels, redirected the morphogenic response with root formation at lower concentrations and callus proliferation on explants cultured with higher amounts of the inhibitor.
These data provide evidence that the transport of calcium and sodium play an important role in cell competence and thidiazuron-induced somatic embryogenesis.