中文摘要：

光合作用是自然生态系统能量流动的基础,植物光合特性决定了生态系统初级生产力的高低.植物不同生长阶段光合特性既对生态系统能量的输入有重要影响,也是种群更新发育的主要驱动因子.在森林生态系统中,优势种的光合生理生态特性影响着整个生态系统的结构和功能.伏牛山自然保护区地处北亚热带到南暖温带交错地带,保存着完整的森林生态系统类型.栓皮栎（Quercus variabilis）作为低海拔区域的主要优势种,更新良好,分层明显.采用Li-6400 光合仪和荧光仪等对不同生长阶段栓皮栎植株（乔木、灌木与幼苗）进行野外光合测定,并分别测定其叶绿素含量.结果表明：（1）与栓皮栎乔木和灌木相比,栓皮栎幼苗的表观量子效率最高,叶片叶绿素含量最高,暗呼吸速率最低,光补偿点最低;（2）与栓皮栎灌木和幼苗相比,栓皮栎乔木对高光的适应能力最强,叶绿素含量最低,栓皮栎的“光合午休”现象并不存在,各层净光合速率日变化主要受光强控制;（3）栓皮栎乔木的PSⅡ最大光化学量子效率最高,幼苗最低;（4）栓皮栎乔木、灌木和幼苗的气孔导度和蒸腾速率均表现为上午高于下午,栓皮栎灌木和幼苗的水分利用效率表现为上午高于下午,而栓皮栎乔木水分利用效率则表现为下午高于上午.不同生长阶段栓皮栎植株光合生理生态特性的这种差异化使它们能适应不同的环境.栓皮栎各层长势良好,更新力强,具有正向演替的内在驱动力.

英文摘要：

Photosynthesis is the basis of energy flow in natural ecosystems and plants′photosynthesis characteristics deter?mine primary productivity of an ecosystem. Plant photosynthetic characteristics, though varying with different plant devel?opmental stages,are not only an important factor influencing energy input of the eco?system, but also a major driving factor of regeneration and development of plant communities. In a forest ecosystem, photosynthetic physiologico?ecological charac?teristics of its dominant species affects the structure and function of the whole eco?system. The Funiu Mountain National Nature Reserve, sitting in the transitional zone between the north subtropics and the south warm?temperate,has preserved an intact type of forest ecosystem. Quercus variabilis, as its main dominant species in areas of low altitude, regenerates nicely forming distinct layers. Photosynthesis of the plants of different development stages ( arbor, shrub and seedling) was measured with a Li-6400 photosynthetic meter and a fluorimeter in the field, and chlorophyll contents in the plants deter?mined in the laboratory. Results show that ( 1) the plant at its seedling stage is the highest in apparent quantum yield and in chlorophyll content, but the lowest in dark respiration rate and in light compensation point; ( 2) the plant at its arbor stage is the highest in high?light adaptability, but the lowest in chlorophyll content, and does not show any phenomenon of midday depression, and diurnal variation of its net photosynthesis at different layers is mainly governed by light intensity;(3)the plant at its arbor stage is the highest in PSⅡ maximum photochemical quantum yield, while the plant at its seed? ling, the lowest;and ( 4) the plant, regardless of growth stage, is higher in the morning than in the afternoon in stomatal conductance and in transpiration rate;and in water use efficiency, too, at all the stages, except the arbor stage, when it goes reversely. Such divergences of the plant in photosynthetic characteristics