Capturing variation in floral shape; a virtual3D based morphospace for Pelargonium
- Published
- Accepted
- Subject Areas
- Biodiversity, Evolutionary Studies, Plant Science
- Keywords
- geometric morphometrics, Pelargonium, floral shape, virtual3D, morphospace, bootstrap
- Copyright
- © 2019 van de Kerke 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
- 2019. Capturing variation in floral shape; a virtual3D based morphospace for Pelargonium. PeerJ Preprints 7:e27867v1 https://doi.org/10.7287/peerj.preprints.27867v1
Abstract
Background. Variation in floral shapes has long fascinated biologists and its modelling enables testing of evolutionary hypotheses. Recent comparative studies that explore floral shape have largely ignored 3D floral shape. We propose quantifying floral shape by using geometric morphometrics on a 3D model based on 2D photographical data and demonstrate its performance in capturing shape variation.
Methods. This approach offers unique benefits to complement established imaging techniques i) by enabling adequate coverage of the potential morphospace of large and diverse flowering-plant clades; (ii) by circumventing asynchronicity in anthesis of different floral parts; and (iii) by incorporating variation in copy number of floral organs within structures. We demonstrate our approach by analysing 90 florally-diverse species of the Southern African genus Pelargonium (Geraniaceae). We quantify Pelargonium floral shapes using 117 landmarks and show similarities in reconstructed morphospaces for spur, corolla (2D datasets), and a combined 3D dataset.
Results. Our results indicate that Pelargonium species differ in floral shape, which can also vary extensively within a species. PCA results of the reconstructed 3D floral models are highly congruent with the separate 2D morphospaces, indicating it is an accurate, virtual, representation of floral shape. Through our approach, we find that adding the third dimension to the data is crucial to accurately interpret the manner of, as well as levels of, shape variation in flowers.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Taxonomic sampling of SPUR and PETAL datasets
Taxonomic sampling of species included in the study. Including individuals per SPUR/PETAL dataset, with locality data and individual number/STEU number when available
R script Analyse flower shape separate
Supplementary R script describing steps for the analysis of floral morphology on SPUR and PETAL datasets separately using Geometric Morphometric Modelling.
R script Rescale and Combine datasets
Supplementary R script describing the steps developed to combine the separate SPUR and PETAL datasets into virtual3D individuals and perform a bootstrapping sampling to evaluate consistancy in the virtually created flowers.
R script Analysing virtual3D dataset
Supplementary R script describing steps for the analysis of floral morphology on virtual3D using Geometric Morphometric Modelling.
Mean consensus configuration and Procrustes residuals for SPUR and PETAL datasets
Supplementary figure showing mean shape and spread of Procrustes residuals per landmark for (A) SPUR and (B) PETAL datasets
PC scores
PC scores for SPUR, PETAL, and virtual3D datasets.