A revised evolutionary history of Poales: origins and diversification. (4th April 2014)

• Record Type: Journal Article
• Authors: Bouchenak‐Khelladi, Yanis; Muasya, A. Muthama; Linder, H. Peter
• Is Part Of: Botanical journal of the Linnean Society. Volume 175:Number 1(2014:May)
• Page Start: 4
• Page End: 16
• Publication Date: 2014-04-04
• Subjects: Botany -- Periodicals; 580
• DOI: 10.1111/boj.12160
• Languages: English
• ISSNs: 0024-4074

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Poales represents more than one‐third of all monocotyledons (<italic>c</italic>. 20 000 species in 16 families) and constitutes a microcosm of the angiosperms. The extreme variation in species richness among the families of Poales is still not understood: Poaceae includes ∼10 000 species, whereas six families have fewer than ten species. Here, using the largest phylogenetic analysis of Poales to date, molecular dating, ancestral reconstructions and diversification analyses, we develop a macro‐evolutionary and macro‐ecological approach to seek correlates for changing diversification patterns. We show that the poalean families diverged in the Late Cretaceous, a time of high levels of CO<sub>2</sub> and high rainfall. Our habitat reconstructions indicate that Poales inhabited open and dry habitats in this environment. We also demonstrate that lineages with CO<sub>2</sub>‐concentrating mechanisms inhabiting dry and open environments exhibited higher diversification rates than C<sub>3</sub>, shade and wet lineages. CO<sub>2</sub>‐concentrating mechanisms counteract the effects of low atmospheric CO<sub>2</sub> and reduce phototranspiration. It is believed that the parallel evolution of C<sub>4</sub> and CAM (Crassulacean acid metabolism) photosynthesis in Poaceae, Cyperaceae and Bromeliaceae is an adaptation to changes in atmospheric CO<sub>2</sub> concentrations. Combinations of extrinsic and intrinsic factors might have played a role in shifts in diversification rates and may explain the variation in species richness in Poales. © 2014 The Linnean Society of London, <italic>Botanical Journal of the Linnean Society</italic>, 2014, <bold>175</bold>, 4–16.</p> </abstract>