Comparative Algal and Byrophyte Physiology
Graham, Linda E. , Ecker, Alice , Kim, Eunsoo .
Production of resistant organic carbon and utilization of labile carbon by terrestrial charophyceans and bryophytes.
A series of previous studies showed that: 1) Certain bryophyte tissues and parts of some aquatic charophycean algae survive both rotting and high temperature acid hydrolysis (acetolysis) treatments, 2) resistance correlates with specific cell wall autofluorescence consistent with presence of polyphenolics, 3) modern resistant structures resemble enigmatic fossils linked to early land plants, and 4) quantitative measures of resistant C produced by modern proxy mosses suggests that prevascular land plants impacted Earth’s global carbon cycle. More recent studies show that the charophycean Coleochaete scutata, when grown in air occurs as unicells or aggregates with thick, resistant, autofluorescent cell walls, and that when slowly desiccated, the liverwort Blasia pusilla generates a surprising amount of resistant C. These results suggest that environmental stresses affect the ecophysiological responses of modern terrestrial charophyceans and bryophytes. To the extent that modern charophyceans and bryophytes serve as reasonable proxies for prevascular terrestrial vegetation, these results also help to explain the fossil record of prevascular land plants and suggest their C-cycle impacts. Comparative data for organic carbon utilization provide additional insight. Under stressful environmental conditions that reduce photosynthetic productivity, organic C uptake could subsidize the cost of producing resistant polyphenolic compounds, which improve survival by reducing the impacts of microbial attack and UV.
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1 - University of Wisconsin Madison, Department of Botany, Birge Hall, 430 Lincoln Drive, Madison, Wisconsin, 53706-1381, USA
2 - University of Wisconsin-Madison, Botany, 430 Lincoln Dr., Madison, WI, 53706, USA
3 - Dalhousie University, Biochemistry, 5850 College Street, Halifax, Nova Scotia, B3H 4N5, Canada
resistant and labile C.
Presentation Type: Symposium or Colloquium Presentation
Location: Stevens 4/Hilton
Date: Tuesday, July 10th, 2007
Time: 8:30 AM