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INITIAL VASCULARIZATION OF THE VEGETATIVE SHOOT OF ABIES CONCOLOR
Author(s) -
Parke Robert V.
Publication year - 1963
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1963.tb07215.x
Subject(s) - biology , primordium , shoot , botany , tracheid , meristem , phloem , crown (dentistry) , phyllotaxis , xylem , medicine , biochemistry , dentistry , gene
P arke , R obert V. (Colorado State U., Fort Collins.) Initial vascularization of the vegetative shoot, of Abies concolor. Amer. Jour. Bot. 50(5): 464–469. Illus. 1963.—In the dormant winter bud, the future vascular system of the shoot exists as a rather ill‐defined system of procambial strands, which extends acropetally from the scale traces through a plate of thick‐walled, deeply staining cells, the crown, and into the axis and the numerous foliar primordia making up the telescoped shoot. Each foliar primordium receives a single procambial strand or leaf trace. The procambial strands differentiate acropetally. No differentiated vascular tissue was observed in the dormant shoot. As the shoot elongates in the spring, vascular differentiation progresses at a rapid rate. In the leaf traces, protophloem differentiates acropetally. The protoxylem, which appears first in the axial region of the trace, differentiates acropetally into the foliar primordium and basipetally into the stem. The first‐formed phloem elements are short‐lived. They are nucleate and without sieve areas. In the protoxylem, the first‐formed tracheids are mostly of the annular or spiral‐thickened type.