Strong conservatism of floral morphology during the rapid diversification of the genus Helianthemum
Metadatos
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Wyley
Materia
Breeding system Cistaceae Evolutionary radiation Floral morphology Floral trait Helianthemum Mediterranean basin Trait conservatism Trait evolution
Date
2023Referencia bibliográfica
Martín‐Hernanz, S., R. G. Albaladejo, S. Lavergne, E. Rubio, M. Marín‐Rodulfo, J. Arroyo, and A. Aparicio. 2023. Strong conservatism of floral morphology during the rapid diversification of the genus Helianthemum. American Journal of Botany e16155. [https://doi.org/10.1002/ajb2.16155]
Patrocinador
Spanish Government CGL2014-52459-P CGL2017-82465-P; Next Generation funds of the European Union through a Margarita Salas postdoctoral contract; Spanish Sistema Nacional de Garantia Juvenil y del Programa Operativo de Empleo Juvenil 2014-2020Résumé
Premise: Divergence of floral morphology and breeding systems are often expected to
be linked to angiosperm diversification and environmental niche divergence. However,
available evidence for such relationships is not generalizable due to different taxonomic,
geographical and time scales. The Palearctic genus Helianthemum shows the highest
diversity of the family Cistaceae in terms of breeding systems, floral traits, and
environmental conditions as a result of three recent evolutionary radiations since
the Late Miocene. Here, we investigated the tempo and mode of evolution of floral
morphology in the genus and its link with species diversification and environmental
niche divergence.
Methods: We quantified 18 floral traits from 83 taxa and applied phylogenetic
comparative methods using a robust phylogenetic framework based on genotypingby‐
sequencing data.
Results: We found three different floral morphologies, putatively related to three
different breeding systems: type I, characterized by small flowers without herkogamy
and low pollen to ovule ratio; type II, represented by large flowers with approach
herkogamy and intermediate pollen to ovule ratio; and type III, featured by small
flowers with reverse herkogamy and the highest pollen to ovule ratio. Each
morphology has been highly conserved across each radiation and has evolved
independently of species diversification and ecological niche divergence.
Conclusions: The combined results of trait, niche, and species diversification
ultimately recovered a pattern of potentially non‐adaptive radiations in Helianthemum
and highlight the idea that evolutionary radiations can be decoupled from
floral morphology evolution even in lineages that diversified in heterogeneous
environments as the Mediterranean Basin.