Carbohydrate and lipid levels in two Polytrichum moss species growing on the Alaskan tundra

Abstract

Two tundra Polytrichum moss species were sampled in the field near Barrow, Alaska, three times during the growing season. Lipid, sugar, and starch concentrations of the green above ground shoots and below ground rhizomes were analyzed. Lipid and TNC (sugar + starch) concentrations were higher in Polytrichum commune growing on raised polygon rims than in Polytrichum alpinum. There were no significant differences between the two populations of P. alpinum. Green parts had significantly higher lipid concentrations than rhizomes in P. commune but not in P. alpinum. Both species had significantly higher sugar concentration in green shoots and higher starch concentrations in the rhizome and sugar concentration varied significantly in both species. Seasonal variation of TNC concentration levels were significant only in P. commune. A statistically significant positive relationship was found between lipid and TNC concentration while a stronger statistically significant negative relationship was found between sugar and starch concentration. The first is interpreted as an adaptation to drought in surface waxes and osmoticum while the second is interpreted as conversion indicator depending on tissue and use. Polytrichum mosses resemble evergreen vascular plants in their seasonal stability of these compound groups.

An experimental comparison of chemical traits and litter decomposition rates in a diverse range of subarctic bryophyte, lichen and vascular plant species

“…Furthermore, availability and type of conductive tissue (Hébant 1977) might influence mass loss, enabling redistribution of easily decomposable components (e.g. Sveinbjörnsson & Oechel 1991; Hakala & Sewón 1992). The lower R 2 for non‐ Sphagnum mosses suggests that indeed further division of this large and heterogeneous group is likely to improve mass loss predictions.…”