Light intensity is a major environmental factor affecting the growth and survival of trees in a forest. The effect of light reduction on photosynthesis and photorespiration of an evergreen broad-leaved tree, Phoebe bournei (Hemsley) Yang was examined with three levels of full light, 50.5% light, and 21.8% light. The results showed that shading led to significant increase in plant height and crown diameter. Light-saturated leaf photosynthetic rate (A_max), maximal carboxylation activity (V_cmax), maximum electron transfer rate (J_max), stomatal conductance (g_s), mesophyll conductance (g_m) and chloroplast CO₂ concentration (C_c) significantly increased in response to shade. Photorespiratory CO₂ release rate (PR) was higher in plants grown under shade conditions than under full light. The relative limitations of g_m (l_m) was higher than the relative limitations of g_s (l_s) and the relative limitations of biochemical factors (l_b) in leaves of P. bournei grown under full light, whereas l_m was lower than l_s and l_b under shade. Our results suggest that increase of photosynthesis in P. bournei leaves grown under shade is associated with enhanced CO₂ diffusion and biochemistry. And we propose that enhancement of the photorespiratory is essential for shade leaves to improve photosynthesis.

光强度是影响森林中树木生长和存活的主要环境因素。用三种水平的全光照，50.5％光照和21.8％光照水平研究了减光对常绿阔叶树Phoebe bournei（Hemsley）Yang的光合作用和光呼吸的影响。结果表明，遮荫导致植物高度和树冠直径显着增加。光饱和叶片的光合速率（A _max），最大羧化活性（V _cmax），最大电子传递速率（J _max），气孔导度（g _s），叶肉导度（g _m）和叶绿体CO ₂浓度（C _c）显着增加对阴影的响应。在荫凉条件下生长的植物中的光呼吸CO ₂释放速率（PR）高于在全光照下。的相对局限性克_米（升_米）比的相对限制更高克_小号（升_小号）和生化因子（相对限制升_b中的叶子）P。本尼在全光照下生长，而l _m低于l _s和l _b在阴影下。我们的结果表明，在阴凉条件下生长的伯氏疟原虫叶片中光合作用的增加与增强的CO ₂扩散和生物化学有关。并且我们提出光呼吸的增强对于遮荫叶子改善光合作用至关重要。