Initiation of embryogenic callus and suspension cultures, and improved embryo regeneration from protoplasts, of white spruce (Picea glauca)

Abstract

Rapid and high frequency somatic embryo regeneration from protoplasts isolated from 10 embryogenic cell lines of white spruce (Picea glauca) is reported. Embryogenic callus was initiated from immature zygotic embryos as source material for protoplast isolation. Individual cell lines exhibited different capabilities for sustained growth. Protoplast plating efficiencies depended on the concentrations of macroelements included in the medium. Using a medium with reduced salts, individual protoplasts developed directly into embryos with no disorganized growth period. Protoplasts from newly established suspension cultures regenerated to recognizable somatic embryos within 8 days of culture. This embryo development was faster than that from protoplasts isolated from longer term suspension cultures. However, the latter suspensions yielded more protoplasts, displayed higher plating efficiencies, and differed in their response to media.