A PRONOUNCED SYNERGISTIC EFFECT OF ABSCISIC-ACID AND 6-BENZYLADENINE ON NORWAY SPRUCE (PICEA-ABIES L KARST) SOMATIC EMBRYO MATURATION

Embryonal-suspensor masses from immature and mature zygotic embryos of Norway spruce (Picea abies L.Karst) were transferred from maintenance to maturation regime on modified Arnold and Eriksson medium with abscisic acid (1.0, 7.6 or 15.2-mu-M) either in the presence or absence of 6-benzyladenine (0.5-10.0-mu-M), followed by continuous cultivation on abscisic acid-containing medium. Supplement of 6-benzyladenine in abscisic acid-containing medium for one or two subcultures resulted in a sharp increase of cumulative recovery of mature somatic embryos per g fresh weight of embryonal-suspensor mass (about 10 times). Somatic embryos were succesfully germinated and transferred ex vitrum.