THE SERIAL OBSERVATION OF EMBRYOGENESIS IN A CARROT CELL SUSPENSION CULTURE

Abstract

SUMMARYSerial observations were made of the early stages of somatic embryogenesis in a cell suspension culture of carrot (Daucus carota L. cv. ‘Kurodagosun’) using a series of cell clusters which divided synchronously. Three phases were recognized in each of which the rate of cell division was different: the first phase (0 to 3 days) during which cells divided slowly, the second phase (3 to 4 days) during which cells divided very rapidly in the determined locus of the cell cluster, leading to the formation of globular embryos, and the third phase (4 to 6 days) during which cell division occurred at a slower rate than the second phase. Three regions were distinguishable in the cell clusters at the end of the second phase: a transparent region destined to develop into the shoot, an opaque region destined to develop into the root and another opaque region which had ceased to grow, suggesting that the determination of differentiation had already occurred by the end of the second phase. The rapid cell division which occurred in the second phase is considered to be a characteristic event in embryogenesis.