Oecologia

, Volume 130, Issue 3, pp 373–379

The ecological role of orientation in tropical convolvulaceous flowers

  • Sandra Patiño
  • Chris Jeffree
  • John Grace

DOI: 10.1007/s00442-001-0824-1

Cite this article as:
Patiño, S., Jeffree, C. & Grace, J. Oecologia (2002) 130: 373. doi:10.1007/s00442-001-0824-1

Abstract.

Flowers of Ipomoea pes-caprae and Merremia borneensis show a preferred orientation, pointing in the general direction of the sun but not exactly tracking the sun. They demonstrated no diurnal heliotropism but strong seasonal heliotropism. The possible effects of this non-random orientation on the heat balance of the flower and the possible consequences on pollination were studied by measuring gynoecium temperature and insect visitation. Differently treated flowers were used to measure gynoecia temperature along with the microclimate: intact flowers, flowers with corollas removed, flowers with the stile and stamens removed, shaded flowers, and flowers constrained to be facing away from the sun. The lowest gynoecium temperature was achieved when the flowers were not constrained and not greased. It is concluded that the natural position of the flower, as well as transpiration, ensures that the temperature of the gynoecium does not reach dangerous levels. Insects preferentially visited sunlit flowers that were free to adopt their natural orientation.

Heliotropism Pollination Convolvulaceae Morning glory Tropical flowers

Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  • Sandra Patiño
    • 1
  • Chris Jeffree
    • 2
  • John Grace
    • 1
  1. 1.Institute of Ecology and Resource Management, The University of Edinburgh, Darwin Building, Mayfield Road, Edinburgh EH9 3JU, UK
  2. 2.Institute of Cell and Molecular Biology, Biological Sciences Electron Microscope Facility, The University of Edinburgh, Daniel Rutherford Building, Mayfield Road, Edinburgh, EH9 3JH, UK
  3. 3.Present address: Instituto Humboldt, Calle 37, 8–40 Mezanne, Santafe de Bogota, Colombia