Regional variation in nitrogen, protein and chlorophyll concentration in Dicranum majus - a reciprocal transplantation experiment

A transplantation experiment was performed to investigate whether differences in nitrogen, protein and chlorophyll concentrations in Dicranum majus Sm. from two areas with different amounts of atmospheric nitrogen deposition, were of genetic origin, environmentally induced or a combination of both factors. Intact samples of D. majus carpets (diameter 20 cm) were reciprocally transplanted between two Picea abies forests, one located in southern (high-N site) and the other in central Norway (low-N site). Four and 16 months after transplantation the nitrogen, protein and chlorophyll concentrations were still higher in moss plants from southern Norway irrespective of growing site. The possibility that the persistence of concentration differences is due to inherent differences in morphology, growth, nitrogen uptake and assimilation rates is discussed. As the experiment lasted for only 16 months and moss plants might be able to recycle nitrogen, an influence of environmental factors cannot be eliminated.