Message - 7th IAL Symposium

The 7 th International Association for Lichenology Symposium 2012
(4B-O5) Submission ID: IAL0137- 00001
ASSESSMENT OF THE PHENOTYPIC PLASTICITY OF UMBILICARIA DECUSSATA ACROSS
ECOPHYSIOLOGICAL STUDIES WITH SEVEN POPULATIONS WORLDWIDE.
Vivas M. 1 , Pérez-Ortega S. 2 , Pintado A. 3 , Näsholm T. 4 , Sancho L. 3
1 Biología Vegetal II, Universidad Complutense, Madrid, Spain
2 MNCN, CSIC, Madrid, Spain
3 Biología Vegetal II, Universidad Complutense, Facultad de Farmacia, Madrid, Spain
4 Forest Ecology and Management, Sveriges Lantbruksuniversitet, Umeå, Sweden
Umbilicaria decussata (Umbilicariaceae, Lecanorales) has a bipolar (arctic-alpine) distribution,
appearing in many of the highest mountains in tropical and temperate regions, as well as in polar regions.
This wide distribution has led us to try to understand its adaptive strategy studying its photosynthetic capacity
and trying to relate it, by means of statistical modelling, with other measured parameters such as chlorophyll,
ergosterol, chitin, amino acids and sugar contents, total carbon and nitrogen concentrations, as well as some
climatic parameters. Umbilicaria decussata specimens were then collected on Mount Kilimanjaro (4,400 m.a.s.l.,
Tanzania), Iztaccihuatl volcano (4,300 m.a.s.l., Mexico), two localities in Chilean Andes (2,000 and 2,700 m.a.s.l.),
Mount Kosciuszko (2,050 m.a.s.l., Australia), and two localities in Spain (Pyrenees, 2,600 m.a.s.l. and Sistema
Central, 2,400 m.a.s.l.). Photosynthetic performance was assessed by gas exchange measurements, using an
open flow system at temperatures between 0 and 25ºC and light intensities ranging from 0 to 1,200 μmol m -2 s -1 .
Chlorophyll was quantified by spectrophotometry according, and ergosterol, chitin, amino acids and sugars
were quantified by different chromatographic methods. C and N were also measured. The most remarkable
difference between populations was found in Mexican samples, which showed maximal photosynthetic yield in a
dry weight basis, as well as highest ergosterol, amino acid, sugar and N content and lowest chitin to ergosterol
ratio, fraction of arginine in the amino acid pool, ribitol to mannitol ratio and carbon to nitrogen ratio, revealing
a more active metabolism. When all data were analysed together, C to N ratio and average temperature of the
coldest month were found to be highly influential on photosynthetic potential activity, showing the importance of
both metabolic and climatic variables.
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4B-O