C:N:P stoichiometric indicator of net primary production of Cynodon dactylon (Linn.) Pers. in the riparian zone of a Three Gorges tributary

Net primary production (NPP) was strongly influenced by the flooding stress, which is closely related to carbon (C), nitrogen (N) and phosphorus (P) allocation in plant aboveground (leaf-stem) and belowground (root) biomass. However, the relationship of NPP with the C:N:P stoichiometric ratio in plant tissues remains unknown, especially in the riparian zone of the Three Gorges Reservoir (TGR). In this study, the leaf-stem and root C, N, P content and biomass of Cynodon dactylon (Linn.) Pers. (C. dactylon) were investigated at the 145-155m, 155-165m and 165-175m altitudes of the riparian zone in TGR tributary-Pengxi River. The results showed that the biomass and NPP of C. dactylon had a similar trend along the riparian zone altitudes. The root showed much lower N and P content, but much higher N and P use efficiency with higher C:N and C:P ratio than that of leaf-stem under N limitation condition. Hydrological and C:N:P stoichiometric variables could predict 68% of the NPP variance. NPP ...