An investigation of paedomorphic secondary xylem and secondary woodiness in Xanthorhiza simplicissima, Coreopsis gigantea, and Mahonia bealei

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Max W. Dulin (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Bruce Kirchoff

Abstract: The stem and secondary xylem anatomy of Xanthorhiza simplicissima, Coreopsis gigantea, and Mahonia bealei are described and characterized in the study. One focus of the study was to determine the degree of paedomorphosis in the secondary xylem of the three plants. Another goal was to assess their woodiness in a phylogenetic context to determine how their woodiness was derived (whether from woody or nonwoody ancestors). Quantitative measurements and observations from slides and macerations were done using light microscopy and confocal microscopy. The secondary xylem of all three species has a degree of paedomorphosis. Coreopsis gigantea has the greatest degree. It possesses vessel elements whose length either decreases or remains the same across the xylem, vessels with pseudoscalariform lateral wall pitting and simple perforation plates, raylessness, libriform fibers, and abundant xylary parenchyma. Xanthorhiza simplicissima has an intermediate degree, possessing decreasing vessel element lengths, libriform fibers, and upright ray cells. Mahonia bealei has only the paedomorphic characteristics of stable vessel element lengths and libriform fibers. Phylogenetic analysis indicates the species are secondarily woody. A major conclusion is that the degree of paedomorphosis reflects the species release from mechanical requirements.

Additional Information

Language: English
Date: 2008
Coreopsis gigantea, Mahonia bealei, Paedomorphosis of the secondary xylem, Secondary woodiness, Secondary xylem anatomy, Xanthorhiza simplicissima
Xylem $x Morphology.
Woody plants $x Anatomy.
Stems (Botany)

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