Characterization of sympatric Platanthera bifolia and Platanthera chlorantha (Orchidaceae) populations with intermediate plants

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1 Earth and Life Institute - Biodiversity Research Centre, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
2 Agroecology & Pollination Group, Landscape Ecology & Plant Production Systems, Université Libre de Bruxelles, Brussels, Belgium
3 Department of Biology, University of Naples Federico II, Napoli, Italy
4 Unit of General Chemistry, Université Libre de Bruxelles, Brussels, Belgium
DOI
10.7287/peerj.preprints.3279v1
Published
Accepted
Subject Areas
Ecology, Evolutionary Studies, Genetics, Plant Science
Keywords
Platanthera, Orchidaceae, Hybridization, Moth pollination, Female fitness, Floral scent, Reproductive isolation, Phenotypic selection, Genetic markers, Morphometrics
Copyright
© 2017 Esposito et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Esposito F, Vereecken NJ, Gammella M, Rinaldi R, Laurent P, Tyteca D. 2017. Characterization of sympatric Platanthera bifolia and Platanthera chlorantha (Orchidaceae) populations with intermediate plants. PeerJ Preprints 5:e3279v1

Abstract

Platanthera bifolia and P. chlorantha are terrestrial and rewarding orchids with a wide Eurasian distribution. Although genetically closely related, they exhibit significant morphological, phenological and ecological differences that maintain reproductive isolation between the species. However, where both species co-occur, individuals with intermediate phenotypic traits, often considered as hybrids, are frequently observed. Here, we combined neutral genetic markers (AFLPs), morphometrics and floral scent analysis (GC-MS) to investigate two mixed Platanthera populations where morphologically intermediate plants were found. Self-pollination experiments revealed a low level of autogamy and artificial crossings combined with assessments of fruit set and seed viability, showed compatibility between the two species. The results of the genetic analyses showed the same genetic patterns of morphologically intermediate individuals with the P. bifolia group. These results are corroborated also by floral scent analyses, which confirmed a strong similarity in floral scent composition between intermediate morphotypes and P. bifolia. Therefore, this study provided a much more detailed picture of the genetic structure of a sympatric zone between two closely allied species and supports the hypothesis that intermediate morphotypes in sympatry could reflect an adaptive evolution in response to local pollinator-mediated selection.

Author Comment

This is a submission to PeerJ for review.

Supplemental Information

Morphological data from allopatric populations (summarized in Table 2)

DOI: 10.7287/peerj.preprints.3279v1/supp-1

Morphological data from Botton sympatric population (summarized in Table 2)

DOI: 10.7287/peerj.preprints.3279v1/supp-2

Morphological data from Bois Niau sympatric population (summarized in Table 2)

DOI: 10.7287/peerj.preprints.3279v1/supp-3

Genotype frequencies of species-specific markers in P. bifolia, P. chlorantha species and intermediate morphotypes of two sympatric zones (Table 3)

DOI: 10.7287/peerj.preprints.3279v1/supp-4

Floral scent profile (Table 4)

DOI: 10.7287/peerj.preprints.3279v1/supp-5

Number of seeds (total and viable - see text)

DOI: 10.7287/peerj.preprints.3279v1/supp-6

Viability index (calculated from the data in the previous file - see text)

DOI: 10.7287/peerj.preprints.3279v1/supp-7