2004 SIVB CONGRESS SYMPOSIUM PROCEEDING: MECHANISMS OF SOMATIC EMBRYOGENESIS IN CARROT SUSPENSION CULTURES –– MORPHOLOGY, PHYSIOLOGY, BIOCHEMISTRY, AND MOLECULAR BIOLOGY

Various aspects of somatic embryogenesis in carrot suspension cultures were reviewed on the basis of results obtained in our laboratory. We have established high-frequency and synchronous somatic embryogenesis systems needed for biochemical and molecular analysis. Using these systems, four phases of somatic embryogenesis were identified. The importance of expression of polarities in these phases, particularly from single cells to embryogenic cell clusters, in determining somatic embryogenesis, is emphasized. At the molecular level, genes expressed during somatic embryogenesis were described, and they were classified into three categories: (1) genes involved in cell division, (2) genes involved in organ formation, and (3) genes specific for the process of somatic embryogenesis. From the results obtained, it is concluded that discrete developmental phases in carrot somatic embryogenesis are characterized by distinct biochemical and molecular events, but much remains to be understood.