Photosynthesis in lichen populations from different altitudes in Swedish lapland

摘要

Carbon dioxide assimilation was measured in situ and in a laboratory experiment in two lichen species from two altitudes near the tree-line at Abisko, northern Sweden,Cetraria nivalisandNephroma arcticum. The altitudinal and horizontal differences between the sites were 850 m and 2,000 m, respectively. The results showed two ecophysiological responses in each species, one “alpine” and one “forest” response. It is hypothesized that these differences are mainly due to an ccotypic differentiation of the