亚热带12种人工幼树光响应模型拟合及光合特性分析

    Fitting of the Light Response Model and Analysis of the Photosynthetic Characteristics of 12 Kinds of Subtropical Artificial Saplings

    • 摘要: 光合-光响应模型是研究树种光合特性至关重要的方法。采用直角双曲线模型(RH)、非直角双曲线模型(NRH)、直角双曲线修正模型(MRH)和指数模型(EM)等4种常用光响应模型分别对12种亚热带人工幼树进行光响应曲线拟合,比较和分析各模型的光响应参数和拟合优度,来探究亚热带12种人工幼树的最适模型和光合特性。结果表明:4种模型拟合决定系数(R2)都在0.962 7以上,在光补偿点(LCP)、最大净光合速率(Pnmax)、表观量子效率(AQE)拟合上,4种模型拟合效果相差不大,但NRH拟合精度最高,MRH的光饱和点(LSP)拟合效果最好。同时,在拟合光响应曲线时还应考虑数据类型,观察曲线是否出现平稳状态,而不是蛮目套用模型进行拟合。光合参数的聚类分析表明,米老排、桂花和马尾松的耐强光能力最强,樟树的光合潜能最大。通过优劣解距离法分析可知,柳杉的耐阴性能力最强,桂花的耐阴性能力最弱,耐阴性能力最强的阔叶树种是浙江楠,可用于马尾松和杉木人工林阔叶化改造,提高人工林生产力。

       

      Abstract: The photosynthetic-light response model is an important method to study the photosynthetic characteristics of tree species. Four common light response models including the rectangular hyperbolic model (RH), the non-rectangular hyperbolic model (NRH), the modified rectangular hyperbolic model (MRH) and the exponential model (EM) were used to fit the light response curves of 12 kinds of subtropical artificial saplings. The light response parameters and the goodness of fitting of each model were compared and analyzed to explore the optimal model and the photosynthetic characteristics of 12 kinds of subtropical artificial saplings. The results showed that: the coefficient of determination (R2) of the four models were all above 0.962 7. In the fitting of light compensation point (LCP), maximum net photosynthetic rate (Pnmax) and apparent quantum efficiency (AQE), the fitting effects of the four models were not much different, but NRH had the highest fitting accuracy, and MRH had the best fitting effect of light saturation point (LSP). At the same time, when fitting the light response curve, the data type should also be considered to observe whether the curve appeared the stationary state, rather than blindly using the model for fitting. The cluster analysis of photosynthetic parameters showed that, Mytilaria laosensis, Osmanthus fragrans and Pinus massoniana had the strongest tolerance to strong light, and Cinnamomum camphor had the strongest photosynthetic potential. According to the analysis of superior-inferior solution distance method, the shade tolerance capability of Cryptomeria japonica was the strongest, while that of Osmanthus fragrans was the weakest. The broad-leaved tree species with the strongest shade tolerance capability was Phoebe chekiangensis, which could be used for the broadleaf transformation of Pinus massoniana and Cunninghamia lanceolata plantations, thus to improve the productivity of plantations.

       

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