Regulation of somatic embryogenesis in celery cell suspensions - 2. Early detection of embryogenic potential and the induction of synchronized cell cultures

The regulation of somatic embryogenesis in celery (Apium graveolens L.) was studied to determine means of increasing its efficiency. Highly embryogenic cell lines were achieved by inducing cell cultures from in vitro plants which were previously regenerated from somatic embryos ('secondary' cell lines). The early detection of embryogenic potential of new cell lines was found to be regulated by 2,4-dichlorophenoxyacetic acid, mannitol and culture duration. Less frequent subculturing allowed embryogenic potential to be expressed earlier. Increased synchronization of celery somatic embryos was induced by two means: adding abscisic acid to the regeneration medium; and segregating the embryos by sieving them through serial metal mesh screens. When abscisic acid was removed from the growth medium, its effects became quickly transient. Embryos of 1400 μm in size provided the best growth rate and uniformity.