Norway Spruce Somatic Embryogenesis: High Frequency Initiation from Light Cultured Mature Embryos Shirley A. Verhagen and Steven

Somatic embryos and rooted plantlets have been regenerated from light-initiated embryogenic callus derived from mature embryos of Picea abies stored seeds. Under a 16 hour photoperiod, mature zygotic embryos were cultured on a modified half-strength Murashige-Skoog medium without NH4NO3 and supplemented with 5 mM glutamine, 4.5 pM N6-benzyladenine (BA) and 10.7 PM naphthalene-acetic acid (NAA) or 10 pM 2,4-dichlorophenoxyacetic acid (2,4-D). White translucent embryogenic callus, proliferating from the callusing hypocotyl region after 3 weeks incubation, was isolated from the green non-embryogenic tissue and subcultured for over 12 months. Upon transfer of the embryogenic callus to medium containing abscisic acid (ABA) and indole-3-butyric acid (IBA), somatic embryos proceeded to mature, elongating and forming a ring of cotyledonary leaves similar to those of a zygotic embryo. Transferred to medium without growth regulators, the somatic embryos "germinated", producing plantlets with green cotyledons, elongated hypocotyls and primary roots.