Trait-based approaches are often widely used in ecological research to predict or explain the complex ecological processes at both individual and ecosystem levels. Leaf function with morphological and physiological traits can play important roles in plan growth, survival, reproduction in natural environments. The aim of this study is 1) to determine the differences of leaf traits between both the species and the functional groups in a swamp meadow; 2) to explore the relationship between different leaf morphological traits and physiological traits. Methods
Gas exchanges of 51 species (in 14 families) were measured on six fully expand health leaves (from different individual plants) using a portable photosynthesis system in the field during the peak of growing season. The leaf morphological traits was measured based on 6 single leaves form different individuals, include the net photosynthesis rate (Pn), transpiration rate (Tr), specific leaf area (SLA), relative leaf water content (LWC), leaf area (LA) and the water use efficiency (WUE = Pn/Tr). Important findings
Result showed that there were significant interspecific differences in the investigated traits as described in above methods. Among the traits, the LWC (coefficient of variation, CV = 0.11) was ranged from 58.12% to 81.83%, 0.0088-0.0278 m2·g-1 for the SLA (CV = 0.27), and 0.51 cm2 to 100.90 cm2 for the LA (CV = 1.73), while the range of 4.25-19.23 μmol CO2·m-2·s-1, 2.89-12.81 mmol H2O·m-2·s-1 and 0.56-3.76 μmol CO2·mmol-1 H2O for Pn (CV = 0.33), Tr (CV = 0.33), and WUE (CV = 0.36), respectively. There were also significant differences between the functional groups (sedge, grass and forbs) for these traits. Forbs have larger LA and higher LWC than sedge and grass; Grass have higher WUE and SLA than those of others; while Sedge have higher Pn. Our result also showed there were high correlation between Pn and SLA, WUE and LWC, indicated the strong impacts of leaf morphology on the gas exchange physiology. The SLA was also related to gas exchange traits both among species and functional groups, while the LWC was only among species and LA among functional groups. In conclusion, significant differences in these functional traits among species suggest that these species could vary in resource use and growth form in their community ecosystem. Also the difference among the functional groups in these traits indicates the resource use of the community would be largely influenced by its species composition, especially the differences of functional groups. The research finding will help to better understanding of the ecosystem function in alpine swamp meadow with related management implication.