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Two cytotype niche shifts are of different magnitude in Solidago gigantea
Author(s) -
Martino Maria,
Semple John C.,
Beck James B.
Publication year - 2020
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/ajb2.1556
Subject(s) - biology , gigantea , herbarium , range (aeronautics) , ploidy , evolutionary biology , microsatellite , niche , botany , ecology , allele , genetics , materials science , composite material , gene
Premise Polyploidy may serve to contribute to range size if autopolyploid cytotypes are adapted to differing ecological conditions. This study aims to establish the geographic distribution of cytotypes within the giant goldenrod ( Solidago gigantea ), and to assess whether cytotypes exhibit differing ecological tolerances and morphology. Methods A range‐wide set of 629 Solidago gigantea individuals was obtained through field collecting, sampling from herbarium specimens, and incorporating existing chromosome counts. Cytotype of each unknown sample was estimated by observing allele numbers at twelve microsatellite loci, a strategy that was assessed by comparing estimated to known cytotype in 20 chromosome‐counted samples. Abiotic ecological differentiation was assessed for two transitions: diploid‐tetraploid and tetraploid‐hexaploid. Morphological differentiation among cytotypes was assessed. Results Microsatellite repeat variation accurately estimated cytotype in 85% of samples for which ploidy was known. Applying this approach to samples of unknown ploidy established that the three cytotypes are non‐randomly distributed. Although niche modeling and MANOVA approaches identified significant differences in macro‐climatic conditions for both cytotype transitions, the tetraploid to hexaploid transition was more substantial. Leaf length and width did not differ among cytotypes. Although leaf vestiture exhibited strong trends, no absolute differences were observed among cytotypes. Conclusions With the largest such study to date, we established niche transitions among giant goldenrod cytotypes of differing magnitudes. Collectively, this suggests that whole‐genome duplication has contributed to Solidago gigantea ’s large range.