Geographic variation in floral allometry suggests repeated transitions between selfing and outcrossing in a mixed mating plant

Summers, Holly E.; Hartwick, Sally M.; Raguso, Robert A. (2015). Geographic variation in floral allometry suggests repeated transitions between selfing and outcrossing in a mixed mating plant. American journal of botany, 102(5), pp. 745-757. Botanical Society of America 10.3732/ajb.1500110

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• Premise of the study: Isometric and allometric scaling of a conserved floral plan could provide a parsimonious mechanism for rapid and reversible transitions between breeding systems. This scaling may occur during transitions between predominant autogamy and xenogamy, contributing to the maintenance of a stable mixed mating system. • Methods: We compared nine disjunct populations of the polytypic, mixed mating species Oenothera flava (Onagraceae) to two parapatric relatives, the obligately xenogamous species O. acutissima and the mixed mating species O. triloba. We compared floral morphology of all taxa using principal component analysis (PCA) and developmental trajectories of floral organs using ANCOVA homogeneity of slopes. • Key results: The PCA revealed both isometric and allometric scaling of a conserved floral plan. Three principal components (PCs) explained 92.5% of the variation in the three species. PC1 predominantly loaded on measures of floral size and accounts for 36% of the variation. PC2 accounted for 35% of the variation, predominantly in traits that influence pollinator handling. PC3 accounted for 22% of the variation, primarily in anther–stigma distance (herkogamy). During O. flava subsp. taraxacoides development, style elongation was accelerated relative to anthers, resulting in positive herkogamy. During O. flava subsp. flava development, style elongation was decelerated, resulting in zero or negative herkogamy. Of the two populations with intermediate morphology, style elongation was accelerated in one population and decelerated in the other. • Conclusions: Isometric and allometric scaling of floral organs in North American Oenothera section Lavauxia drive variation in breeding system. Multiple developmental paths to intermediate phenotypes support the likelihood of multiple mating system transitions.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS) > Plant Development
08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS)

UniBE Contributor:

Summers, Holly

Subjects:

500 Science > 580 Plants (Botany)

ISSN:

0002-9122

Publisher:

Botanical Society of America

Language:

English

Submitter:

Peter Alfred von Ballmoos-Haas

Date Deposited:

08 Jun 2015 14:55

Last Modified:

06 Jul 2017 08:34

Publisher DOI:

10.3732/ajb.1500110

Uncontrolled Keywords:

breeding system, floral traits, geographic variation, isometry, mating system, Onagraceae, outcrossing, pollination, reproductive strategies

URI:

https://boris.unibe.ch/id/eprint/69214

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