EXTRACELLULAR PROTEINS IN EMBRYOGENIC SUSPENSION-CULTURES OF NORWAY SPRUCE (PICEA-ABIES)

Embryogenic cell lines of Norway spruce (Picea abies) varying in growt h habit and morphology were compared as regards profiles of extracellu lar proteins. Similar proteins were detected in the culture medium by SDS PAGE and in vivo labeling experiments, indicating that the protein s were secreted. Approximately 20 protein bands could be detected in t he medium of each cell line. Three of the bands represented glycosylat ed proteins, as revealed by Concanavalin A staining. Some of the secre ted proteins were similar for all tested embryogenic lines of Norway s pruce, others were either specific for a group of cell lines or for in dividual cell lines. A correlation was observed between the morphology of the somatic embryos in a cell line and the presence of secreted pr oteins. The embryogenic cell lines of Norway spruce can be divided int o two main groups, A and B, where A is characterized by somatic embryo s with dense embryoheads and B by somatic embryos with loosely aggrega ted cells in their embryoheads. When proteins secreted from a cell lin e belonging to group A were added to cell lines belonging to group B, the somatic embryos of the B type developed further and became more si milar in morphology to A-type embryos. These observations indicate tha t cell lines belonging to group A secrete certain proteins to the cult ure medium that are essential for the development of somatic embryos o f Norway spruce.