| Abstract Detail
Paleobotanical Section Boyce, C. Kevin [1], Brodribb, Tim J. [2], Feild, Taylor S. [3], Zwieniecki, Maciej A. [4]. Angiosperm leaf evolution put the rain in tropical rainforests. Vein density is shown to be a crucial but overlooked difference between angiosperm and non-angiosperm leaves: over the 380 million year history of laminate leaves, non-angiosperms average only 2 mm/mm2 while the 7 to 17 mm/mm2 densities routinely found among angiosperms are essentially absent in all other plants, living or extinct. We further show that high vein density is a prerequisite for high leaf transpiration rates. Thus, the transpiration-driven recycling of water that is important for sustaining the humid, reliably high rainfall climate of modern tropical rainforests would not have been possible in a pre-angiosperm world. This seemingly inconsequential angiosperm leaf characteristic was essential for the broad geographic spread of continental tropical rainforests and the radiation of their drought-intolerant biota.
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1 - University of Chicago, Department of Geophysical Sciences, 5734 S. Ellis Avenue, Chicago, Illinois, 60637, USA
2 - University of Tasmania, Department of Plant Sciences, Hobart, Tasmania, 7001, Australia
3 - University of Tennessee, Department of Ecology and Evolutionary Biology, Knoxville, TN, 37996, USA
4 - Arnold Arboretum of Harvard University, 125 Arborway, Jamaica Plain, Massachusetts, 02130, USA
Keywords:
venation
Cenozoic
Mesozoic
physiology
paleoclimate.
Presentation Type: Oral Paper:Papers for Sections
Session: 60
Location: 169/Law
Date: Wednesday, July 30th, 2008
Time: 1:45 PM
Number: 60004
Abstract ID:386 |
