Diversification Slowdown in the Cirrhopetalum Alliance (Bulbophyllum, Orchidaceae): Insights From the Evolutionary Dynamics of Crassulacean Acid Metabolism.
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fpls-13-794171.pdf
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3.21 MB
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Resource type
Journal article
Date published
February 3, 2022
Abstract
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.
Funder
| Funder name | Awards |
Kadoorie Farm and Botanic Garden | |
Royal Botanical Gardens, Kew, United Kingdom | Sainsbury Orchid Fellowship |
Journal title
Frontiers in Plant Science
Article number
794171
Publisher
Frontiers Media SA
Place of publication
Lausanne, Switzerland
eISSN
1664-462X
Date accepted
January 10, 2022
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Rights statement
In Copyright