Growth and soluble proteins of cell cultures derived from explants and protoplasts of Pinus pinaster cotyledons

Abstract

Pinus pinaster Ait. cell suspension cultures were derived from chopped cotyledons and from cotyledon protoplasts. When transferred after 12 weeks in culture, growth of both cell types showed a lag of 5 days followed by an exponential phase of 14 days for the protoplast-derived cells and 23 days for the organ-derived cells. During the exponential growth phase, packed cell volume of protoplast-derived cultures increased 7-fold and that of organ-derived cultures 13-fold. During the stationary phase, the diameters of protoplast-derived cells averaged 80 microm and those of organ-derived cells 100 microm. After 30 days, the media containing protoplast-derived and organ-derived cells decreased in osmolarity by 50 and 120 mOs per kg water, respectively, and in pH by 1.4 and 2.0 units, respectively. Throughout the growth cycle, protein content per unit of packed cell volume was always at least 35% higher in the protoplast-derived cultures than in the organ-derived cultures. Two-dimensional electrophoretic separation of soluble proteins revealed three peptides present in protoplast-derived cells that were absent from organ-derived cells and two peptides present in organ-derived cells that were absent from protoplast-derived cells. Other peptides differed quantitatively between the cell types.