关键词: 榆树, 光响应曲线, 模型, 通径分析, 光合能力

Abstract: Using light response curves of photosynthesis for 5 Ulmus plants fitted by 4 kinds of photosynthesis light response models, this paper contrasted the main characteristic parameters of the model of the optical response to explore the difference of each model and different Ulmus.The results showed that the fitting results of different models for the same plant were different, so was the same model for different plants. The rectangular hyperbola  correction model's  (model Ⅲ) fitting degree was the best of the four kinds of models that could reflect the phenomenon of photoinhibition of plants, but the maximum net photosynthetic rate and light compensation point were greatly different with measurements. The summary of this study indicated that exponential model (model Ⅳ) was the best model of photosynthetic light-response curve of the 5 Ulmus. The photosynthetic capacity of Ulmus davidiana Planch was the largest, Ulmus macrocarpa is minimal. Path analysis showed that the dominant factors affecting the photosynthetic were different.

Key words: Ulmus, Light response curves, model, path analysis, photosynthetic capacity