Abstract: In order to establish genetic transformation system of foreign genes on small fruit type of papaya, indirect somatic embryogenesis of immature embryos (90-120 days after pollination) of Carica papaya L. 'Meizhonghong' was studied by histological section and observation with a scanning electron microscope. The results showed that the calli were originated from the epidemic cells of the radicle after 8-12 days of culture. After 26 days of culture, the whole embryonary axis turned into calli which differentiated to translucent and mucous, and dry types. The cross-section results showed the calli consisted of two distinct sectors, a loose friable tissue of outer sectors and compact aggregates of inter sectors. Yellow pre-embryonic complexes were derived from calli of the plumula after 38 days of culture. It was observed that most of morphological somatic embryos were normally developed.

Key words: Carica papaya L., Papaya, Somatic embryogenesis