Somatic Embryogenesis of Ferula assa-foetida

Regenerated plantlets were obtained from Ferula assa-foetida (Apiaceace) through indirect and direct somatic embryogenesis, for the first time. Callus was induced on hypocotyl explants from seedlings of two ecotypes (Shirkooh and Tabas) on Murashige and Skoog (MS) basal medium supplemented with 0.5-4 mg/L kinetin along with 0.1-1 mg/L ?-naphthalene acetic acid (NAA) for 12 weeks. Embryogenic calli developed within 4 weeks after transferring the calli to hormone-free MS medium. Induction/maintenance MS medium supplemented with 1.5 mg/L kinetin and 1 mg/L NAA was most effective and provided a high embryogenesis frequency (31%) associated with a large mean number of mature somatic embryos per explant (8.4) in Tabas ecotype. According to our data, the presence of kinetin in the callus induction medium with NAA enhanced subsequent differentiation of somatic embryos on the hormone-free medium. About 40-50% of regenerated somatic embryos germinated into complete plantlets. Direct somatic embryogenesis without an intervening callus phase was induced from intact seedlings on hormone-free medium within 12 weeks. Embryo induction was observed all over the seedling surface with the highest numbers on hypocotyl segments. By this procedure, the maximum mean number of embryo per seedling was 42 in Shirkooh ecotype and more than 50% of cotyledonary embryos were developed not only into normal plantlets, but rooted simultaneously when cultured on hormone-free MS medium. Also, histological observations revealed different stages of embryogenicity such as globular, heart, torpedo, and cotyledonary stages in F. assa foetida.