Patterns of asymmetry in the twining vine Dalechampia scandens (Euphorbiaceae): ontogenetic and hierarchical perspectives

Authors

  • Christophe Pélabon,

    1. Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway;
    Search for more papers by this author
  • Thomas F. Hansen,

    1. Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA;
    2. Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, Norway;
    Search for more papers by this author
  • Matthew L. Carlson,

    1. Alaska Natural Heritage Program, Environment and Natural Resources Institute, University of Alaska, Anchorage, AK 99501, USA;
    Search for more papers by this author
  • W. Scott Armbruster

    1. Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway;
    2. Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA;
    3. School of Biological Sciences, University of Portsmouth, Portsmouth, Hants PO1 2DY, UK
    Search for more papers by this author

Author for correspondence: Christophe Pélabon Tel: +47 73596282 Fax: +47 73596100 Email: christophe.pelabon@bio.ntnu.no

Summary

  • • We studied patterns of fluctuating asymmetry (FA) in leaves of four populations of the neotropical vine Dalechampia scandens to obtain insight into the origin of leaf FA and the level at which it is controlled. We analysed correlations in signed and unsigned asymmetry at different organizational levels. We also analysed the ontogeny of FA during leaf expansion to test whether asymmetry is regulated during cell expansion, and whether fast-expanding leaves are more or less asymmetrical.
  • • Signed asymmetry was negatively correlated between successive leaves, that is, when the right side of a leaf was larger than the left side, the next leaf on the shoot tended to show the opposite pattern. The magnitude of FA, however, was very weakly correlated among successive leaves or among leaves measured on different shoots.
  • • The direction of asymmetry did not change during leaf expansion, but the relative asymmetry, that is, asymmetry corrected for difference in trait size, decreased during expansion. We found a weak negative relationship between leaf expansion rate and relative asymmetry on the fully expanded leaves.
  • • These results suggest that leaf asymmetry in Dalechampia originates from perturbations in cell proliferation in the stem, creating asymmetries in opposite directions in successive leaves. These asymmetries persist during leaf expansion, but tend to be reduced by unknown mechanisms.

Ancillary