INDUCTION OF SOMATIC EMBRYOGENESIS IN EXCISED COTYLEDONS OF PICEA-GLAUCA AND PICEA-MARIANA

Somatic embryogenesis was induced in the cotyledons of Picea mariana (black spruce) and Picea glauca (white spruce). Exposure of the cotyledons to a high ratio (90:1) of benzyladenine (BA) to napthaleneacetic acid (NAA) for one week before subculturing on media with auxin to cytokinin ratios of 2:1 (2,4-dichlorophenoxyacetic acid: BA) and 50:1 (NAA:BA), improved embryogenic response, especially of P. mariana. Embryonal suspensor callus of both black and white spruce could be multiplied and plantlets regenerated from the somatic embryos. In addition to the embryogenic tissues consisting of embryonal and suspensorial cells, which are typical of conifer tissues cultured in vitro, direct development of somatic embryos was observed for both P. glauca and P. mariana. Also in this case plantlets could be regenerated.