Leaf Nitrogen and Phosphorus Stoichiometry are Closely Linked with Mycorrhizal Type Traits of Legume Species

Arbuscular mycorrhizas (AM) are the most widely symbiosis in terrestrial ecosystem. Leaf N and P are the most important plant functional traits due to their influence on biogeochemical cycling. However, as the notable nitrogen (N) fixing plants, the variations of leaf N, P and N:P and their relationship among mycorrhizal types had been hardly studied based on functional groups. In this study, we studied the leaf N, P and N:P and their relationship between AM and other mycorrhizal types (others) among different functional groups or climate zones. The results indicated that AM improve significantly leaf N and P, while reduce N:P comparing to others. However, the influences of AM and others on leaf N, P and N:P changed with plant functional groups or climate zone. The relationships between leaf N and P, between N and N:P and between P and N:P also exhibit great variation between AM and Others.

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.