SOMATIC EMBRYOGENESIS AND PLANT REGENERATION IN HYOSCYAMUS NIGER

Culture of segments of leaves, petioles, and stems and of germinated seeds and whole ovaries enclosing unpollinated ovules of Hyoscyamus niger in a medium containg 2, 4-dichlorophen-oxyacetic acid caused massive growth of calluses. In cultured germinated seeds and ovaries, calluses were formed from the hypocotyl and placenta, respectively. Leaf and stem explants generally gave rise to hard, white, and compact calluses. Upon transfer of these calluses to an auxin-free medium they regenerated roots or buds but showed no further signs of morphogenesis. Calluses formed on petioles, germinated seeds, and ovaries were a mixture of the white, compact and brown, friable types. Subsequent morphogenesis of the friable calluses in a medium lacking auxin was characterized by the formation of somatic embryos whose pattern of development was similar to that of zygotic embryos.