Canadian Forest Service Publications

Biochemical characterization of black spruce (Picea mariana (Mill.) B.S.P.) somatic embryogenesis and precocious germination. 2003. Beardmore, T. Propagation of Ornamental Plants 3: 3-10.

Year: 2003

Issued by: Atlantic Forestry Centre

Catalog ID: 22862

Language: English

CFS Availability: Order paper copy (free)

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Abstract

Black spruce somatic embryo development was examined at four stages: torpedo, early, mid-, and late-cotyledonary stage embryos. Late-cotyledonary embros when left attached to the embryonal masses germinated precociously. These precociously germinating embroys were examined at four stages: (stage P-1) yellow cotyledons; (stage P-2) green cotyledons; (stage P-3) elongating cotyledons; (stage P-4) elongating hypocotyl. Embryo dry weight increased until the P-1 stage and plateaued, embryo fresh weight increased from the early cotyledon stage to the P-3 stage. Embryo ABA increased throughout development, peaked at the late-cotyledonary stage and declined during precocious germination. Protein content increased throughout development and plateaued by the P-2 stage. The 42-, 31, 30-, 28-, 27-, 21-, and 20-kD seed storage polypeptides were used as developmental markers for somatic embryogenesis. Accumulation of polypeptides was evident in the torpedo stage embryo and they were synthesized throughout development and during precocious germination. A cessation in storage protein synthesis occurred only when hypocotyls elongated. Early cotyledonary embryos germinated when placed on germination media (8 % germination). Germinability increased to 95 % when precocious germinating embryos (P-3 stage) were transferred to germination media. Embryos were not germinable on water until the late-cotyledonary stage (8 % germination) and a maximum germination of 68 % on water was attained by the P-4 stage embryos. These results indicate that precociously germinating embryos continued developmental events (i.e., storage protein synthesis). A decline in the number of storage proteins synthesized occurred only when hypocotyl elongation was evident in P-4 stage embryos.