Abstract

The study investigated the specific leaf area (SLA), leaf photosynthetic rates (P_n), 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 N_m. The above resource capture-, use- and growth-related traits probably clarified the mechanism of the secondary succession in the Loess Plateau.

Key words: Photosynthetic nitrogen use efficiency, specific leaf area, secondary succession, Loess Plateau.

Abbreviation

SLA, Specific leaf area; P_n, leaf photosynthetic rates; PNUE,photosynthetic nitrogen use efficiencies; Chl, leaf chlorophyll content; Nm, leaf nitrogen content per unit dry mass; Na, leaf nitrogen content per unit area.