Oecologia

, Volume 130, Issue 3, pp 373–379

The ecological role of orientation in tropical convolvulaceous flowers

Authors

  • Sandra Patiño
    • Institute of Ecology and Resource Management, The University of Edinburgh, Darwin Building, Mayfield Road, Edinburgh EH9 3JU, UK
  • Chris Jeffree
    • Institute of Cell and Molecular Biology, Biological Sciences Electron Microscope Facility, The University of Edinburgh, Daniel Rutherford Building, Mayfield Road, Edinburgh, EH9 3JH, UK
  • John Grace
    • Institute of Ecology and Resource Management, The University of Edinburgh, Darwin Building, Mayfield Road, Edinburgh EH9 3JU, UK

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