Canadian Forest Service Publications

Natural pigment differences distinguish first and sequent periderms of conifers through a cryofixation and chemical techniques. 1971. Mullick, D.B. Canadian Journal of Botany 49(9): 1703-1711.

Year: 1971

Issued by: Pacific Forestry Centre

Catalog ID: 28398

Language: English

Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1139/b71-240

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Field observations revealed distinctness of the first and sequent periderm pigmentation in each of 40 species from 13 genera of conifers. These distinctions in Abies amabilis (Dougl.) Forbes, Abies grandis (Dougl.) Lindl., Thuja plicata (Donn), and Tsuga heterophylla (Raf.) Sarg. were confirmed by a cryofixation and chemical techniques. The former technique depends upon fixation of tissues by freezing, and microscopic observation of cryostat sections in a frozen state, thus revealing the natural color of the pigments. The first periderm of the aforementioned four species is dark brown. It is replaced invariably by a reddish sequent periderm which always abuts the rhytidome. Additional reddish sequent periderms may continue to arise producing an ever-thickening rhytidomal zone. A second type of sequent periderm, dark brown in color, was found in three of the four species studied. This periderm, whenever present, was found abutting a reddish periderm and never abutting the rhytidome. The pigments are localized exclusively in phellem. The significance of the brownish sequent periderm in rhytidomal scaling and en masse sloughing, and its similarities to the first periderm are discussed.