Organic chemical differentiation within fossil plant cell walls detected with X-ray spectromicroscopy
- C. Kevin Boyce*1,
- George D. Cody2,
- Michael Feser3,
- Chris Jacobsen3,
- Andrew H. Knoll4 and
- Susan Wirick5
- 1Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- 2Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015, USA
- 3Department of Physics, State University of New York, Stony Brook, New York 11794, USA
- 4Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- 5Department of Physics, State University of New York, Stony Brook, New York 11794, USA
Abstract
Organic matter preserved in cell walls of permineralized plant fossils was analyzed by using scanning transmission X-ray microscopy and spectroscopy at energies near the 1s absorption edge of carbon. Microchemical analyses were performed directly on cellulose acetate peels of the fossils, preserving information on the anatomical distribution of organic materials. Individual tracheid walls in both Eocene and Early Devonian fossils exhibit spatially distinct chemical zoning inherited from original wall biopolymers and cell-wall microstructure. Molecular analysis of submicrometer domains using carbon X-ray absorption near-edge spectroscopy documents the differential distribution of hydroxylated aromatic and alcohol (and/or ether) carbon in the inner and outer regions of tracheid walls. This zonation reflects the deposition of lignin and structural polysaccharides in Devonian plants, indicating biochemical and developmental pathways similar to those of living tracheophytes.
Footnotes
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↵*E-mail addresses: Boyce— cboyceoeb.harvard.edu; Codycodygl.ciw.edu
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- Accepted July 18, 2002.
- Received March 27, 2002.
- Revision received July 18, 2002.
- Geological Society of America
