Plantlet Regeneration from Cultured Embryos and Seedling Parts of Red Spruce (Picea rubens Sarg.)

Plantlet regeneration of red spruce (Picea rubens Sarg.) was achieved from mature embryos, cotyledons, and hypocotyl explants. Optimal bud induction was observed on half-strength modified Bornman's (MCM) medium with 10 μM N6-benzyladenine for 14 d. Shoot elongation occurred after transfer to half-strength modified von Arnold and Eriksson's medium. Decreasing sucrose to 2% and addition of conifer-derived activated charcoal enhanced shoot elongation. Low concentrations of cytokinin (0.1 μM) promoted growth of axillary shoots. Rooting was induced on excised shoots by dipping in rooting powder or pulsing in high concentrations of indolebutyric acid plus indoleacetic acid or naphthaleneacetic acid prior to transfer to hormone-free medium. Plantlets grew after transfer to the greenhouse