Somatic embryogenesis in Nicotiana tabacum L.: induction by thidiazuron of direct embryo differentiation from cultured leaf discs.

Induction of somatic embryogenesis by different growth regulators was examined in leaf disc cultures of Nicotiana tabacum L. Direct differentiation of somatic embryos occurred on media supplemented with naphthaleneacetic acid (NAA) and N(6)-benzylaminopurine (BAP). Thidiazuron (N-phenyl-N'-1, 2,3,-thiadiazol-5-ylurea; TDZ) not only substituted for the most effective NAA-BAP combination but also induced a higher frequency of somatic embryogenesis. Regenerated somatic embryos were capable of developing into plants.