Using modern plant trait relationships between observed and theoretical maximum stomatal conductance and vein density to examine patterns of plant macroevolution.
New Phytol
; 209(1): 94-103, 2016 Jan.
Article
en En
| MEDLINE
| ID: mdl-26230251
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 (gmax ) and leaf vein density (Dv ) and physiological measurements including operational stomatal conductance (gop ), saturated (Asat ) and maximum (Amax ) 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 gop , gmax and Dv that together can be used to estimate gas exchange and the photosynthetic capacities of fossils. We showed that acquisition of high gmax 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 gmax (> 1400 mmol m(-2) s(-1) ) would have been capable of maintaining a high Amax as the atmospheric CO2 declined through the Cretaceous, whereas gymnosperms with a low gmax would experience severe photosynthetic penalty. Expansion of the ecophysiological niche space in angiosperms, afforded by coordinated evolution of high gmax , Dv and increased plasticity in gop , adds further functional insights into the mechanisms driving angiosperm speciation.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Transpiración de Plantas
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Magnoliopsida
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Cycadopsida
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Fósiles
Idioma:
En
Revista:
New Phytol
Asunto de la revista:
BOTANICA
Año:
2016
Tipo del documento:
Article
País de afiliación:
Irlanda