岩溶与非岩溶区典型植物最适光合模型和光合特征研究

Studies on Optimal Photosynthetic Biochemical Model and Photosynthetic Characteristics of Typical Plants in Karst and Non-karst Regions

摘要:

为探讨不同生境典型植物光合特征对主要环境因子的响应，选择Ethier&Livingston、Ellsworth和Sharkey等3种光合生化模型拟合我国西南岩溶与非岩溶区8种典型植物的A-Ci曲线。结果表明，用Ethier & Livingston模型拟合的A-Ci曲线要优于Ellsworth模型和Sharkey模型，拟合方程的决定系数（R²）为0.98~0.99（P < 0.01）。从Ethier&Livingston模型拟合的V_cmax和J_max来看，岩溶区和非岩溶区乡土植物间的差异不显著，但都显著低于外来速生植物尾巨桉（Eucalyptus grandis×E.urophylla）。岩溶区和非岩溶区乡土植物的光合特征参数（V_cmax，25和J_max，25）均与空气温度和土壤水分含量呈显著相关（P < 0.05）。除非岩溶区乡土植物的J_max，25外，所有植物的光合特征参数与土壤水分拟合方程的R²均低于其与环境温度的，表明环境温度对典型植物V_cmax，25和J_max，25的影响强于土壤含水量。

Abstract:

The aim was to screen the optimal model in fitting photosynthetic CO₂response curve (A-Ci curve) of plants in different habitats, three biochemical models, including Ethier & Livingston, Ellsworth, and Sharkey model, were used to fit the A-Ci curves of 8 typical plants in karst and non-karst regions of southwest China. Then the photosynthetic parameters and their response to main environmental factors were analyzed. The results showed that Ethier & Livingston model was better than the other two models in fitting A-Ci curve of 8 typical plants, with determination coefficient (R²) from 0.98 to 0.99 (P<0.01). The photosynthetic parameters (V_cmax and J_max) fitted by Ethier & Livingston model had no significant differences between karst and non-karst native plants (P>0.05), but both of them were significantly lower than that of Eucalyptus grandis×E. urophylla. Moreover, V_cmax,25 and J_max,25 of karst and non-karst native plants were significantly correlated with air temperature and soil water content (P<0.05). However, the determination coefficients (R²) between air temperature and V_cmax,25 or J_max,25 were higher than that between soil water content and V_cmax,25/J_max,25 for all plants except of J_max,25 of non-karst native plants. Therefore, these indicated that the influence of air temperature on V_cmax,25 and J_max,25 of typical plants in this area was stronger than that of soil water content.