Response of Leymus chinensis functional traits and aboveground biomass to nitrogen addition in Songnen grassland in northeast China

The adaptive strategy of plant functional traits to resources change is one of the basic problems in ecology. In the present study, 11 plant functional traits and aboveground biomass of Leymus chinensis with different amount of nitrogen addition were determined. The results showed that nitrogen addition had significant effects on leaf chlorophyll a (Cha), chlorophyll b (Chb) and carotenoid (Cad) content, leaf nitrogen concentration (LNC), leaf dry matter content (LDMC), and specific root length (SRL), however, had no effects on leaf phosphorus concentration (LPC), specific leaf area (SLA), leaf thickness (LT), stem specific density (SSD), and plant height (PH). There were significant correlation between Cha, Chb, Cd, LNC, LDMC, SSD and SRL. SLA, LT and PH had no significant correlation with other functional traits. The aboveground biomass of L. chinensis was the highest at 20 g·m-2 nitrogen addition. The aboveground biomass significantly increased with Cha, Chb, Cad, LNC, LPC, and PH increasing, but significantly decreased with LDMC and SSD increasing.