Canadian Forest Service Publications
The structure of freeze-etched bordered-pit membranes of Abies grandis. 1973. Puritch, G.S.; Johnson, R.P.C. Wood Science and Technology 7(4): 256-260.
Issued by: Pacific Forestry Centre
Catalog ID: 28703
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Sapwood, frozen in a conducting state, was freeze-etched for electron microscopy to show undried bordered-pit membranes. These appeared similar in structure to non-aspirated pit membranes observed in wood dried from organic solvents. Freeze-etching showed that, even before drying, the torus is lens-shaped in section and suspended by a margo of large radial strands and numerous smaller fibrils. Globular objects, previously undescribed, whose diameters ranged from 0.3 to 1 m, were found distributed at random on pit membranes and tracheid walls.