Somatic embryogenesis in Picea glauca (white spruce) and Picea mariana (black spruce)

Abstract

Embryogenic callus was initiated from immature embryos of Picea glauca (white spruce) and Picea mariana (black spruce) cultured on defined media supplemented with 2,4-dichlorophenoxyacetic acid (1 × 10−5 M), N6-benzyladenine (5 × 10−6 M), and 1% sucrose. Seeds from cones stored at 4 °C for up to 3 months yielded embryogenic callus. Much higher frequencies of embryogenic callus were obtained from white spruce than from black spruce. Embryogenic callus contained loosely organized cells and somatic embryos of various sizes. The embryos consisted of a cluster of tiny dividing cells (embryonic region) with attached large vacuolated cells (suspensor region). Upon subculture of embrogenic callus to media either lacking growth regulators or with reduced concentrations (5 × 10−7 M, 2,4-dichlorophenoxyacetic acid and 5 × 10−6 M N6-benzyladenine) somatic embryos could be stimulated to develop into plantlets.