Canadian Forest Service Publications

Differences in composition and release rate of volatiles emitted by black spruce seed cones sampled in situ versus ex situ. 1998. Turgeon, J.J.; Brockerhoff, E.G.; Lombardo, D.A.; MacDonald, L.M.; Grant, G.G. Canadian Journal of Forest Research 28: 311-316.

Year: 1998

Issued by: Great Lakes Forestry Centre

Catalog ID: 24447

Language: English

Availability: PDF (request by e-mail)

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The volatile emissions of black spruce (Picea marianu (Mill.) BSP) seed cones still attached to a live 7 m tall tree(in situ) were compared with those of cones from the same tree that had been severed (ex situ).Volatiles were collected simultaneously with a manifold headspace sampling system, adsorbed on PorapakĀ®Q, and the extracts analysed by capillary gas chromatography (GC)andGC- massspectrometry. The relative abundance of the identified constituents, tricyclcnc. aand p-pinene, camphene, sabinenc. p-myrcenc. A-3-carcne. />-cymenc. P-phcllandrenc, limonenc, y-terpincne. a-terpinolcne. camphor, borneol. and bornylacetate differedquantitatively, almostqualitatively, between in situ and ex situ samples. For example, camphene and bornyl acetate represented ca.7% and 12% of total emissions, respectively, of the volatiles from in situ cones andca. 0.9% and <0.2%, respectively, of the volatiles from ex silucones, p-phellandrene and P-pincnc were consistently less abundantin extractsof in situ collections (ca. 4.5%and 22%, respectively) than in those of ex situ collections (ca. 6% and 32%,respectively). Also, the release rate of total monoterpenes from in situ seed cones was approximately twice as high as that from ex situ cones. These results indicate that ex situ sampling does not accurately depict the composition of volatile emissions by seed cones and suggest that tests for biological activity based on such compositions could lead to erroneous conclusions.