Synchronized somatic embryo development in embryogenic suspensions of Fraxinus angustifolia

The synchronization of somatic embryo development in embryogenic suspension cultures is a crucial step in taking advantage of somatic embryogenesis fo r high production potential and reduction of unit cost through automation. In the present study, a synchronous somatic embryogenic system was develope d for Fraxinus angustifolia suspension cultures. High cell density, 6-benzy ladenine (BA.) and 2,4-dichlorophenoxyacetic acid proved essential for the establishment and maintenance of suspension cultures. Low cell density, BA and 1-naphthaleneacetic acid enhanced somatic embryo development. Cell and cell cluster fractionation by density gradient centrifugation in Ficoll sol ution proved useful for separation of subpopulations with differing potenti als for embryo development. A synchronous development of somatic embryos at high frequency was achieved only from the heaviest cell population.