FAHSELT, DIANNE. Department of Plant Sciences, University of Western Ontario, London, Ontario N6A 5B7 CANADA. - Detection of pigments in specimens of recent and subfossil Umbilicaria from north Greenland.
Photosynthetic pigments were found in extant and Late Holocene
subfossil lichens which had been buried beneath ice in north
Greenland. Minor constituents present in nearby conspecific lichens
were not observed in subfossils, but the major pigments of extant
thalli were detetectable. Thus, while concentrations were lower in
subfossils, normal pigments survived glaciation for up to 1350 yr and
could be detected in specimens that had been dry for as long as 4 yr.
Umbilicaria cylindrica, U. krascheninnikovii and U.
hyperborea buried by glacier ice contained chlorophyll a,
in some cases chlorophyll b, and up to seven carotenoids. High
performance liquid chromatography of subfossil extracts revealed a
preponderance of rapidly-eluted peaks, possibly degradation products,
that were relatively inconspicuous in extracts of specimens from
extant populations. Both glaciated and unglaciated samples of U.
hyperborea, which had been stored longer than other species,
yielded the lowest chlorophyll a/b ratios and Fv/Fm values,
indicative of pigment deterioration in dry thalli. In all species
chlorophyll a/chlorophyll b ratios and Fv/Fm readings
were generally lower in subfossils than in comparable extant lichens
which had escaped long-term ice burial.
Key words: carotenoid*, chlorophyll*, Holocene, lichen*, subfossil, Umbilicaria