Diversification Slowdown in the Cirrhopetalum Alliance ( Bulbophyllum , Orchidaceae): Insights From the Evolutionary Dynamics of Crassulacean Acid Metabolism
Evolutionary slowdowns in diversification have been inferred in various plant and animal lineages. Investigation based on diversification models integrated with environmental factors and key characters could provide critical insights into this diversification trend. We evaluate diversification rates...
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Published in | Frontiers in plant science Vol. 13; p. 794171 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Switzerland
Frontiers Media S.A
03.02.2022
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Subjects | |
Online Access | Get full text |
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Summary: | Evolutionary slowdowns in diversification have been inferred in various plant and animal lineages. Investigation based on diversification models integrated with environmental factors and key characters could provide critical insights into this diversification trend. We evaluate diversification rates in the
alliance (
, Orchidaceae subfam. Epidendroideae) using a time-calibrated phylogeny and assess the role of Crassulacean acid metabolism (CAM) as a hypothesised key innovation promoting the spectacular diversity of orchids, especially those with an epiphytic habit. An explosive early speciation in the
alliance is evident, with the origin of CAM providing a short-term advantage under the low atmospheric CO
concentrations (
CO
) associated with cooling and aridification in the late Miocene. A subsequent slowdown of diversification in the
alliance is possibly explained by a failure to keep pace with
CO
dynamics. We further demonstrate that extinction rates in strong CAM lineages are ten times higher than those of C
lineages, with CAM not as evolutionarily labile as previously assumed. These results challenge the role of CAM as a "key innovation" in the diversification of epiphytic orchids. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 This article was submitted to Plant Systematics and Evolution, a section of the journal Frontiers in Plant Science Edited by: Susann Wicke, Humboldt University of Berlin, Germany Reviewed by: Jianquan Liu, Lanzhou University, China; Matthew Pace, New York Botanical Garden, United States |
ISSN: | 1664-462X 1664-462X |
DOI: | 10.3389/fpls.2022.794171 |