Morphogenic and genetic stability in longterm embryogenic cultures and somatic embryos of Norway spruce (Picea abies {L.} Karst).

Embryogenic cultures were initiated from mature zygotic embryos of Picea abies. The somatic embryos in the embryogenic cultures were first stimulated to mature and then either to develop further into plantlets or to differentiate new embryogenic cultures. The procedure was repeated three times during two years. The ability to give rise to new embryogenic cultures or to develop into plantlets was similar for all somatic embryos irrespective of how long they had been cultured in vitro. The nuclear DNA content, measured in a flow cytometer, was estimated at 32 pg/G1 nuclei in seedings developed from zygotic embryos. Nuclei isolated from embryogenic cultures and from plantlets regenerated from somatic embryos had the same DNA content as those isolated from seedlings.