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 regeneration (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 species from differently managed mountain grassland ecosystems (abandoned areas, pastures and meadows) at three study areas in the Eastern Alps. A significant 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 proportionally smaller amount of available resources into P_ml. Despite this close correlation 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 investigated 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 differ significantly from each other. Species from abandoned areas were found to be lower with respect to V_cmax, P_ml, N_L and SLA than species from pastures and meadows, which were not significantly different from each other.