Abstract Detail



Anatomy and Morphology

Chery, Joyce [1], Pace, Marcelo [2], Acevedo-Rodriguez, Pedro [3], Rothfels, Carl [4], Specht, Chelsea [5].

Evolution of strange wood development in a large group of neotropical lianas, Paullinia (Sapindaceae).

Distantly related plant groups have converged upon a unique suite of anatomical traits—the “liana syndrome”—that work in a coordinated fashion to maximize conductance, strength, and flexibility, thus permitting these woody plants to adopt a climbing habit. Extreme elaborations of this liana syndrome can give rise to “vascular cambial variants”, which are unusual stem conformations derived from the alternative activity of the vascular cambium in the formation of wood. The large neotropical liana genus, Paullinia L. (Sapindaceae), has a great diversity of wood morphologies, with some species displaying the simple wood type reminiscent of self-sustaining plants (i.e., trees and shrubs), while others display a cambial variant. In this study, we integrated classical wood ontogeny techniques with molecular phylogenetics and phylogenetic comparative methods to explore the evolution of cambial variant development in Paullinia. We describe six wood ontogenies in Paullinia by studying three stages of development (primary growth, transition stage, and mature wood). Most Paullinia species appear stellate (i.e., star shaped) in cross-sectional view during primary growth. This irregular shape is achieved by the unequal distribution of vascular bundles around the circumference of the stem. Although rare among woody plants, this is the basic bauplan of primary growth in Paullinia, from which five of the six mature wood forms develop from (simple II, phloem wedges, lobed xylem, compound, and successive cambia). To explore the evolution of wood development on the phylogeny, we employed phylogenetic comparative methods to reconstruct ancestral states of primary plant body shape and of mature wood type. Additionally, we tested the hypothesis that the evolution of cambial variants in Paullinia is dependent on first evolving the irregular stellate primary growth confirmation. Our results identify a critical relationship across primary and secondary growth in both the development of cambial variants of an individual plant, and the emergence of these novel forms through evolutionary time.


1 - UC Berkeley, 3040 Valley Life Sciences Bldg #3140, Berkeley, CA, 94720, United States
2 - Universidad Nacional Autónoma de México, Biology, Edificio A, Piso 2: 217, Mexico City, MX
3 - Smithsonian National Museum of Natural History, Botany, 10th St. & Constitution Ave. NW, Washington, DC, 20560, USA
4 - University Of California Berkeley, University Herbarium And Departmenty Of Integrative Biology, 1001 Valley Life Science Building, Berkeley, CA, 94720, United States
5 - Cornell University, Plant Biology, Ithaca, NY, 14853, USA

Keywords:
vascular cambium
Evolution of development
lianas
Sapindaceae
stem development.

Presentation Type: Oral Paper
Number: 0010
Abstract ID:509
Candidate for Awards:Katherine Esau Award


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