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Development and structure of trichotomous branching in Edgeworthia chrysantha (Thymelaeaceae)
Author(s) -
Iwamoto Akitoshi,
Matsumura Yumiko,
Ohba Hideaki,
Murata Jin,
Imaichi Ryoko
Publication year - 2005
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 - 10.3732/ajb.92.8.1350
Subject(s) - primordium , biology , axillary bud , meristem , branching (polymer chemistry) , phyllotaxis , botany , lateral shoot , thymelaeaceae , shoot , apex (geometry) , genetics , gene , tissue culture , materials science , in vitro , composite material
We studied the development and structure of the unusual trichotomous branching of Edgeworthia chrysantha . Three “branch primordia” are formed sequentially on the shoot apex of a main axis and develop into trichotomous branching. The branch primordia are clearly distinguishable from the typical axillary buds of other angiosperms; they develop much more rapidly than axillary buds, and the borders between the branch primordia and shoot apex of the main axis are anatomically unclear. Furthermore, at a later stage, leaves subtending the branch primordia produce typical axillary buds. These results suggest that the trichotomous branching in this species involves the division of the shoot apical meristem. Expression analysis of genes involved in branching or maintenance of the shoot apical meristem in this species should clarify the control mechanism of this novel branching pattern in angiosperms. We also observed the phyllotactic patterns in trichotomous branching and have related these patterns to the shoot system as a whole.