Inter- and intraspecific variation in grass phytolith shape and size: a geometric morphometrics perspective.

Publisher: Oxford University Press Country of Publication: England NLM ID: 0372347 Publication Model: Print Cited Medium: Internet ISSN: 1095-8290 (Electronic) Linking ISSN: 03057364 NLM ISO Abbreviation: Ann Bot Subsets: MEDLINE

Publication: 2002- : Oxford, UK : Oxford University Press
Original Publication: Oxford [etc.]

Fossils* ; Plants*; Analysis of Variance ; Discriminant Analysis ; Principal Component Analysis

Background and Aims: The relative contributions of inter- and intraspecific variation to phytolith shape and size have only been investigated in a limited number of studies. However, a detailed understanding of phytolith variation patterns among populations or even within a single plant specimen is of key importance for the correct taxonomic identification of grass taxa in fossil samples and for the reconstruction of vegetation and environmental conditions in the past. In this study, we used geometric morphometric analysis for the quantification of different sources of phytolith shape and size variation.
Methods: We used landmark-based geometric morphometric methods for the analysis of phytolith shapes in two extant grass species (Brachypodium pinnatum and B. sylvaticum). For each species, 1200 phytoliths were analysed from 12 leaves originating from six plants growing in three populations. Phytolith shape and size data were subjected to multivariate Procrustes analysis of variance (ANOVA), multivariate regression, principal component analysis and linear discriminant analysis.
Key Results: Interspecific variation largely outweighed intraspecific variation with respect to phytolith shape. Individual phytolith shapes were classified with 83 % accuracy into their respective species. Conversely, variation in phytolith shapes within species but among populations, possibly related to environmental heterogeneity, was comparatively low.
Conclusions: Our results imply that phytolith shape relatively closely corresponds to the taxonomic identity of closely related grass species. Moreover, our methodological approach, applied here in phytolith analysis for the first time, enabled the quantification and separation of variation that is not related to species discrimination. Our findings strengthen the role of grass phytoliths in the reconstruction of past vegetation dynamics.
(© The Author(s) 2020. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Comment in: Ann Bot. 2021 Jan 7;127(2):iii-iv. (PMID: 33274374)

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Keywords: Brachypodium pinnatum; Brachypodium sylvaticum; Phytolith analysis; generalized Procrustes superimposition; intraspecific variation; landmark-based geometric morphometrics; paleoecology

Date Created: 20200529 Date Completed: 20210215 Latest Revision: 20210529

20231215

PMC7789106

10.1093/aob/mcaa102

32463863