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The Influence of Pressure on the Differentiation of Secondary Tissues
Claud L. Brown and Karl Sax
American Journal of Botany
Vol. 49, No. 7 (Aug., 1962), pp. 683-691
Published by: Botanical Society of America, Inc.
Stable URL: http://www.jstor.org/stable/2439160
Page Count: 9
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When longitudinal bark strips of Populus trichocarpa and Pinus strobus are separated from the bole wood during early spring and maintained in a humid environment while attached to the parent tree, the cambial zone along the inner surface of the segments rapidly proliferates producing an extensive parenchymatous callus. Subsequently, a new phellogen and cambium differentiate and extend tangentially around the outer periphery of the callus pad, this resulting in the formation of a new stem-like structure. Whenever bark strips are separated from the bole wood by a layer of polyethylene plastic film and held firmly against the tree by externally applied pressure, the cambium continues to function normally, setting aside derivatives which differentiate and mature into normal, elongate xylary and phloic elements. The importance of mutual pressures and spatial relationships in controlling patterns of differentiation in secondary tissues is clearly demonstrated.
American Journal of Botany © 1962 Botanical Society of America, Inc.