Variation in Leaf Nitrogen and Phosphorus Stoichiometry in Different Functional Groups of Legumes

The legume is notable owing to their symbiotic nitrogen (N) fixing ability. Usually, higher leaf N concentration and N to phosphorus (P) ratio (N:P) in legumes than non-legumes. However, the variations of leaf N, P and N:P and their relationship had been hardly studied based on functional groups. In this study, we studied the leaf N, P and N:P and their relationship among different functional groups. The results showed that the average values of leaf N, P and N:P ratios for all legumes were 27.33 mg g(-1), 1.27 mg g(-1) and 21.94, respectively. Leaf N (36.96 mg g(-1)) and P (2.15 mg g(-1)) of herbaceous legumes are significantly higher than N (24.97 mg g(-1)) and P (1.18 mg g(-1)) in woody plants, respectively. Moreover, leaf N, P and N:P of shrub markedly higher than them in tree. Leaf N and P are always higher in deciduous than evergreen legumes. A negative correlation was found between leaf N:P and P in overall and different functional groups of legumes.