Regensburg 1998 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
AOE: Agrar- und Ökosystemphysik
AOE 2: Pflanzen und Boden
AOE 2.2: Hauptvortrag
Montag, 23. März 1998, 14:30–15:00, T
Dehydration below percolation threshold and freezing protection mechanism in lichens as observed by NMR and electric conductivity — •H. Haranczyk1, M. Wnek1, S. Gaydzinski2, J. Grandjean1, and M. Olech3 — 1Institute of Physics, Jagiellonian University, Krakow — 2Institute of Botany, Jagiellonian University, Krakow — 3Institute of Chemistry, University of Liege, Liege
Antarctic lichens are proper system to investigate the ability of living organisms to survive in extreme dehydration and at low temperature. Proton magnetic relaxation times and spectra were recorded in function of varied temperature and hydration of thallus. The electrical conductivity hydration traces performed in room temperature showed the dehydration of lichen thallus below the two-dimensional water percolation threshold whereas the NMR relaxometry suggests that the thallus dehydrates even below water clustering point. At slow cooling down the thallus, the mechanism of transfer of water from the loosely bound pool to the non-freezable tightly bound fraction manifests which may be responsible for the freezing protection of lichens.