中文摘要：

本文选择桂林会仙石灰岩峰丛洼地不同地貌部位的扶芳藤为研究对象，运用光合作用测定系统（LI-6400）测定其光合生理指标，对比分析洼地和山腰两种不同地貌部位扶芳藤的光合日动态和光强响应特征，并对其光合参数进行了测定及相关分析。结果表明：洼地和山腰扶芳藤的净光合速率（net photosyntheticrate，Pn）日变化均为双峰型，且Pn日变化存在明显的“午休”现象。不同地貌部位不同时间段的扶芳藤净光合速率Pn与气孔导度（stomatal conductance，Gs）、胞间CO2浓度（intercellular CO2 concentration，Ci）、蒸腾速率（transpiration rate，Tr）、叶面温度（leaf temperature，TI）以及光合有效辐射（photosynthetic available radiation，PAR）等光合参数的相关关系有明显的差异。洼地和山腰扶芳藤的光补偿点、光饱和点和表观量子效率大小表明扶芳藤既有一定的耐荫能力，又能适应一定强度的阳光辐射。两者间的差异反映了扶芳藤对不同地貌部位岩溶环境具有较强的适应能力。

英文摘要：

In the essay, the Euonymus fortunei in differemt geomorphological positions of Guilin＇s Huixian Karst Peak-cluster billabong area are studied with the LI-6400 portable photosynthetic system to probe into the photosynthetic physiological indexes. Though the contrast of the plant＇s photosynthesis diurnal variation and the characteristics of photoresponse, which grows in billabong and in moutainside, the determination and the relative analysis are conducted in accordance with its photosynthetic parameters.The results indicate that the diurnal change of net photosynthetic rate （Pn） ofEuonymus fortunei presented a double-peak curve, which showed obvious midday depression（noon break）.There is an obvious difference of the relationship between the Euonymus fortunei＇s Pn and the indexes of Gs, Ci, Yr, T1 and PAR in different geomorphological positions at different time. The LCP, LSP and AQY of Euonymus fortunei in billabong and moutainside indicates that the plant falls into a family between shade plants and sun plants, and that the Euonymus fortunei has some properties of resisting humid and sunshine. And what＇ s more, the two differemt features of the plant reflect its different adaptability in different geomorphological positions of Karst environment.