Absence of meristems in androgenic embryos of Datura metel (L.) induces secondary embryogenesis in vitro

• Removal of meristems of androgenic embryos of Datura metel induced secondary embryos on their hypocotyls.
• This phenomenon mimics the removal of apical dominancy in plants.
• This could potentially produce secondary embryos from recalcitrant species for in vitro propagation.

The induction of secondary embryos in androgenic and zygotic embryos of Datura metel (L.) (Solanaceae) was investigated by excising their shoot and root meristems and culturing the hypocotyls on Nitsch medium. Androgenic embryos produced secondary embryos on the hypocotyl. Histological sections showed secondary embryo development was independent of maternal tissue with no connection to the maternal vascular system. The zygotic embryos produced shoot buds and adventitious roots from the cut surface. Shoot buds had vascular connections with the maternal tissue. Excision of both meristems produced more secondary embryos than excision of the apical meristem alone. Excision of apical meristems in embryogenically competent immature embryos and their in vitro culture could potentially produce secondary embryos on the hypocotyls. The significance of these results is the clonal multiplication of the primary embryo at an early stage of embryo development. The meristem excision steps are easily performed under sterile conditions.