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Using modern plant trait relationships between observed and theoretical maximum stomatal conductance and vein density to examine patterns of plant macroevolution

Mcelwain, JC and Yiotis, C and Lawson, T (2016) 'Using modern plant trait relationships between observed and theoretical maximum stomatal conductance and vein density to examine patterns of plant macroevolution.' New Phytologist, 209 (1). 94 - 103. ISSN 0028-646X

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Abstract

Understanding the drivers of geological-scale patterns in plant macroevolution is limited by a hesitancy to use measurable traits of fossils to infer palaeoecophysiological function. Here, scaling relationships between morphological traits including maximum theoretical stomatal conductance (g ) and leaf vein density (D ) and physiological measurements including operational stomatal conductance (g ), saturated (A ) and maximum (A ) assimilation rates were investigated for 18 extant taxa in order to improve understanding of angiosperm diversification in the Cretaceous. Our study demonstrated significant relationships between g , g and D that together can be used to estimate gas exchange and the photosynthetic capacities of fossils. We showed that acquisition of high g in angiosperms conferred a competitive advantage over gymnosperms by increasing the dynamic range (plasticity) of their gas exchange and expanding their ecophysiological niche space. We suggest that species with a high g (> 1400 mmol m s ) would have been capable of maintaining a high A as the atmospheric CO declined through the Cretaceous, whereas gymnosperms with a low g would experience severe photosynthetic penalty. Expansion of the ecophysiological niche space in angiosperms, afforded by coordinated evolution of high g , D and increased plasticity in g , adds further functional insights into the mechanisms driving angiosperm speciation. max v op sat max op max v max max max 2 max max v op -2 -1

Item Type: Article
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Science and Health > Life Sciences, School of
Depositing User: Jim Jamieson
Date Deposited: 05 Aug 2015 09:05
Last Modified: 31 Mar 2021 00:15
URI: http://repository.essex.ac.uk/id/eprint/14471

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