Germination of encapsulated embryos of interior spruce (Picea glauca engelmannii complex) and black spruce (Picea mariana Mill.).

Interior spruce (Picea glauca engelmannii complex) and black spruce (Picea mariana Mill.) cotyledonary somatic embryos were encapsulated in sodium alginate. Somatic embryo viability was retained, but germination occurred at a reduced frequency compared with the equivalent zygotic embryos. The addition of 0.5% (w/v) activated charcoal to the alginate capsule significantly enhanced root development and germination for somatic embryos but not for zygotic embryos. The possibility of developing an artiflcal endosperm was also investigated, by addition of Litvay (Litvay et al. 1981) nutrients with or without 90 mM sucrose to the alginate-charcoal capsule. This treatment significantly enhanced root development for all embryo categories with the exception of black spruce somatic embryos. Encapsulated and non-encapsulated somatic embryos survived one month cold storage at 4 °C without reduction in germination frequency.

Cryopreservation of interior spruce (Picea glauca engelmanni complex) embryogenic cultures.

Embryogenic cultures of interior spruce derived from 12 full-sib families were subjected to cryopreservation, with a 97 % success rate for 357 genotypes. Analyses suggested that cryotolerance was not related to family ranking (height increment), embryogenic potential or culture dispersability in suspension, and long-term storage in or above liquid nitrogen did not affect regenerative potential. By contrast, differences in cryotolerance among cell lines appeared to be prevalent in certain families. Analysis with a DNA fingerprinting probe used for clonal identification demonstrated no evidence of somaclonal variation as a result of cryopreservation. The results of this work indicate the applicability of cryopreservation as a long-term storage strategy for spruce embryogenic cultures from a wide genetic background.