Scientists investigate the early evolution of tissue systems in plants.
Mapping the evolution of life on Earth requires a detailed understanding of the fossil record, and scientists are using synchrotron-based technologies to look back—way, way back—at the cell structure and chemistry of the earliest known woody plant. Dr. Christine Strullu-Derrien and colleagues used the Canadian Light Source’s SM beamline at the University of Saskatchewan to study Armoricaphyton chateaupannense, an extinct woody plant that is about 400 million years old. Their research focused on lignin, an organic compound in the plant tracheids, elongated cells that help transport water and mineral salts. Lignin makes the cells walls rigid and less water permeable, thereby improving the conductivity of their vascular system.
Strullu-Derrien, a scientific associate at the Natural History Museum in London, England and the Natural History Museum in Paris, France, had described A. chateaupannense some years ago and returned to it for this project.
“Studies have been done previously on Devonian plants but they were not woody,” she said. “A. chateaupannense is the earliest known woody plant and it’s preserved in both 2D form as flat carbonaceous films and 3D organo-mineral structures. This allows for comparison to be done between the two types of preservation,” she said.
Although the fossils used in the study were collected in the Armorican Massif, a geologically significant region of hills and flatlands in western France, Strullu-Derrien said early Devonian woody plants have also been found in New Brunswick and the Gaspé area in Quebec “although these are 10 million years younger than the French one.”
Image: A, photograph of Armoricaphyton chateaupannense preserved in 2D as carbonaceous thin films. B, SEM image of a transverse section of an axis of a specimen of A. chateaupannense preserved in 3D showing the radially aligned tracheids.