Document Type

Article

Publication Date

6-1-2017

Publication Title

Journal of chemical ecology

ISSN

1573-1561

Volume

43

Issue

6

First Page

599

Last Page

607

DOI

http://dx.doi.org/10.1007/s10886-017-0854-8

PubMed ID

28589423

Abstract

Plants produce a variety of secondary metabolites that function as a defense against their natural enemies. Production of these secondary metabolites is genetically controlled, but is also phenotypically plastic and varies in response to both biotic and abiotic factors. Therefore, plant species may vary widely in their chemical defenses and such variation can be evident at temporal, spatial and tissue levels. Focusing on the chemical defenses of a native Colorado wildflower, Penstemon virgatus, we assessed the variation in iridoid glycoside (IG) content across two non-consecutive growing seasons, six natural populations and three tissue types: leaves, stems and flowers. Our results indicate that P. virgatus plants contain high concentrations of IGs (mean = 23.36% dry weight of leaves) and that IGs were differentially allocated among tissue types. Leaves contained the highest concentration of IGs, which varied quantitatively between sampling years, among plant populations, and plant parts. We also quantified leaf herbivore damage at all six populations but we found very little herbivore damage. Our study indicates that the IG concentrations of P. virgatus plants are both spatially and temporally variable. Furthermore, the high concentrations of secondary metabolites combined with the low levels of damage suggest that these plants are well defended against generalist herbivores.

Comments

This is a post-print version of "The Perennial Penstemon: Variation in Defensive Chemistry Across Years, Populations, and Tissues" published in the Journal of Chemical Ecology.

© Springer Science+Business Media New York 2017

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