Inter-specific variation of the biochemical limitation to photosynthesis and related leaf traits of 30 species from mountain grassland ecosystems under different land use

The maximum rate of carboxylation (V-cmax) and the potential rate of RuBP r egeneration (P-ml, which equals J(max)/4), as well as leaf nitrogen content (N-L) and specific leaf area (SLA), were studied in sun leaves of 30 speci es from differently managed mountain grassland ecosystems (abandoned areas, pastures and meadows) at three study areas in the Eastern Alps. A signific ant correlation between V-cmax and P-ml across the investigated species was observed. In comparison to a previous survey on the relationship between P -ml and V-cmax, the investigated species were found to invest a proportiona lly smaller amount of available resources into P-ml. Despite this close cor relation between V-cmax and P-ml, variation in the V-cmax-N-L and P-ml-N-L relationships was large, indicating that the investigated species differed widely in their respective nitrogen use efficiencies. Among the investigate d species, dwarf shrubs were characterized by significantly lower values of V-cmax, P-ml and N-L compared to graminoids and forbs, which did not diffe r significantly from each other. Species from abandoned areas were found to be lower,vith respect to V-cmax, P-ml, N-L and SLA than species from pastu res and meadows, which were not significantly different from each other.