Generality of leaf traits relationships of dominant species along the secondary succession in the Loess Plateau of China

The study investigated the specific leaf area (SLA), leaf photosynthetic rates (Pn), leaf nitrogen contents (on mass and area bases, Nm and Na, respectively) and nitrogen use efficiencies (PNUE) of 18 dominant species of four secondary succession groups in the Loess Plateau. The leaf SLA, N m, P n and PNUE significantly differed among the different secondary succession groups ( P<0.05), but the leaf N a and leaf chlorophyll content (Chl) did not differ. SLA varied in a high → low → high pattern with the secondary succession, reaching the lowest point in the early forest community. The N m and Chl showed a double peak curve with the secondary succession and peaked in the shrub community. Of all the species, the photosynthetic nitrogen use efficiencies were positively correlated with the SLA, but negatively correlated with the N a. The SLA of all the species negatively correlated with the N a, but weak positively correlated with the Nm. The above resource capture-, use- and growth-related traits probably clarified the mechanism of the secondary succession in the Loess Plateau.