Spatiotemporal Floral Scent Variation of Penstemon digitalis

J Chem Ecol. 2015 Jul;41(7):641-50. doi: 10.1007/s10886-015-0599-1. Epub 2015 Jul 2.


Variability in floral volatile emissions can occur temporally through floral development, during diel cycles, as well as spatially within a flower. These spatiotemporal patterns are hypothesized to provide additional information to floral visitors, but they are rarely measured, and their attendant hypotheses are even more rarely tested. In Penstemon digitalis, a plant whose floral scent has been shown to be under strong phenotypic selection for seed fitness, we investigated spatiotemporal variation in floral scent by using dynamic headspace collection, respectively solid-phase microextraction, and analyzed the volatile samples by combined gas chromatography-mass spectrometry. Total volatile emission was greatest during flowering and peak pollinator activity hours, suggesting its importance in mediating ecological interactions. We also detected tissue and reward-specific compounds, consistent with the hypothesis that complexity in floral scent composition reflects several ecological functions. In particular, we found tissue-specific scents for the stigma, stamens, and staminode (a modified sterile stamen common to all Penstemons). Our findings emphasize the dynamic nature of floral scents and highlight a need for greater understanding of ecological and physiological mechanisms driving spatiotemporal patterns in scent production.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acyclic Monoterpenes
  • Flowers / chemistry
  • Flowers / physiology*
  • Gas Chromatography-Mass Spectrometry
  • Monoterpenes / analysis
  • Odorants / analysis*
  • Penstemon / chemistry
  • Penstemon / physiology*
  • Pollination
  • Volatile Organic Compounds / analysis*


  • Acyclic Monoterpenes
  • Monoterpenes
  • Volatile Organic Compounds
  • linalool