Abstract: Five light response models of photosynthesis (exponential, rectangular hyperbolic, non-rectangular hyperbolic, quadratic function, and modified rectangular hyperbola) were applied to analyze the light response curves ofMagnolia sinostellata seedlings under different light intensity and moisture conditions. The results showed that: (1) The fitting accuracy of those models followed the order: exponential > modified rectangular hyperbola > rectangular hyperbola > non-rectangular hyperbola > quadratic function. (2) The light response parameters in fitting effect indicated that the exponential model could result in more accurate maximum net photosynthetic rate (P_nmax) and light saturation point (LSP). The rectangular hyperbolic model was the best one at figuring out light compensation point (LCP). The non-rectangular hyperbolic model was more reasonable to figure out dark respiration rate (R_d). (3)M. sinostellata seedlings could adapt to the environment with weak light and flowing water, but not for strong shading and waterlogging environment.

Key words: light and heavy fraction, ammonium nitrogen, nitrate nitrogen, straw returning