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THE VASCULAR TRANSITION REGION OF HELIANTHUS ANNUUS. I. BILATERAL AND UNILATERAL PATTERNS OF DIFFERENTIATION
Author(s) -
Scheirer Daniel C.,
Hillson Charles J.
Publication year - 1973
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.1537-2197.1973.tb10223.x
Subject(s) - helianthus annuus , biology , transition (genetics) , phloem , botany , helianthus , anatomy , evolutionary biology , sunflower , genetics , horticulture , gene
The vascular transition region of Helianthus annuus L. may exhibit either a unilateral or a bilateral differentiation of primary phloem groups. The unilateral type of transition has been previously described but the bilateral type with its two variations is described here for the first time. The three patterns of transition are compared, and the significance of the variability of transition regions is discussed in terms of basic transition types and phylogenetic importance.