Abstract: The relationships among leaf traits under different densities are important for understanding the relationship between the physical construction and physiological metabolism of plant leaves. We examined the relationship between chlorophyll content and leaf area, leaf thickness of Liguaria virgaureawith different population densities in Gahai alpine wetland. The L. virgaurea populations were divided into three densities: high (I, 171-240 bundles·m^-2), medium (II, 101-170 bundles·m^-2) and low (III, 30-100 bundles·m^-2). Three plots (1 m×1 m) were established for each density to investigate plant leaf traits. The estimation analysis of standardized major axis and Pearson correlation analysis were used to examine the allometric relationship between chlorophyll content and leaf area and thickness. The results showed that, with decreasing density of L. virgaurea population, density displayed a decrease-increase trend, vegetation coverage decreased, while plant height and soil moisture increased. Leaf area and chlorophyll content decreased gradually, and leaf thickness and specific photosynthetically active radiation inside the community decreased gradually. Moreover, leaf net photosynthetic rate and transpiration rate displayed a decrease-increase trend. Chlorophyll content was significantly negatively correlated with leaf area (P<0.05) but positively correlated with leaf thickness (P<0.05). Our results indicated that L. virgaurea growing in highdensity wetland has high chlorophyll content but small and thick leaves, whereas that growing in low-density wetland has low chlorophyll content but big and thin leaves. Our results reflect the adaptation of resource use strategies and photosynthetic product accumulation pattern of plants to the heterogeneity of environmental factors such as light conditions.

Key words: temperature sensitivity (Q₁₀), hydro-thermal factor, soil respiration, desertification reversion, soil property