Abstract: Understanding the variation of leaf functional traits of plant species from different elevations provides basis for assessing the adaptive strategies of plants and predicting the potential shifts in plant species distribution, community dynamic, and forest ecosystem structure and function under climate changes. In this study, we quantified the variations in leaf traits of two species (Rhododendron simsii and Pinus taiwanensis) commonly growing at three elevations (>1900, 1500-1700, 1000-1300 m above sea level) in Wuyi Mountain National Nature Reserve in Jiangxi Province. Leaf traits related to defence (i.e.,concentrations of lipids, lignin, soluble phenolics, organic acids, total nonstructural carbohydrates, total structural carbohydrates), traits related to growth (i.e., specific leaf area, concentrations of protein, minerals, carbon (C), nitrogen (N), phosphorus (P), and N/P ratio), and leaf construction costs (CC) were compared for species from different elevations. Correlations among the different leaf traits were also examined. The results showed that 
leaf CC of both species did not vary significantly among the elevations. The concentrations of soluble phenolics  in leaves of both species significantly decreased with elevation, while foliar protein, N and P concentrations increased. With increasing elevation, lignin concentrations in leaves of R. simsii decreased, whereas the concentrations of total structural carbohydrates and minerals in leaves of R. simsi and the concentration of total nonstructural carbohydrates in leaves of P. taiwanensis increased. Leaf CC of R. simsii was negatively correlated with the concentrations of organic acids and minerals and specific leaf area, and positively correlated with the concentration of total nonstructural carbohydrates. Leaf CC of P. taiwanensis was positively correlated with the concentration of soluble phenolics. The concentration of leaf protein was positively correlated with the concentration of leaf total structural carbohydrates in R. simsii, and positively correlated with the concentration of leaf nonstructural carbohydrates in P. taiwanensis. The variations of leaf functional traits related to growth and defence across the altitudinal gradient indicate that both species could adapt to environmental change.

Key words: elevation, leaf construction cost, leaf functional trait, Rhododendron simsii, Pinus taiwanensis, adaptation.