巨尾桉与针叶树种光合生理特性的比较研究

摘要

Objective]To explore whether Guilin region is suitable for the growth of Eucalyptus grandis × E.urophylla,we made comparison of photosynthetic physiological characteristics among Eucalyptus grandis × E.urophylla plantations and leguminous mixed forest in Lingtian country.[Methods]The Li-6400 portable photosynthesis systemwas used to measure the net photosynthetic rate (Pn)and the daily variation of photosynthetic physiolog-ical factors among Eucalyptus grandis × E.urophylla,Pinus massoniana, and Cunninghamia lanceolata in spring.Correlation analysis was used to understand the rela-tionship of Pn and other photosynthetic physiological factors.[Results]Pn of all tree species showed double-peak characteristic in spring.Photosynthetically active radiation (PAR), stomatal conductance (Gs),transpiration rate (Tr),and intercellular CO2 density are main factors affecting Pn daily variation.[Conclusion]Eucalyptus grandis ×E.urophylla has high water use efficiency (WUE),light use efficiency (LUE ) and CO2 use efficiency and adapt to mountain habitat with fast growing in Guilin.%【目的】比较桂林市灵田乡人工巨尾桉（Eucalyptus grandis × E．urophylla）林和针叶混交林的光合生理特性，探究该地区是否适应巨尾桉的生长。【方法】采用 Li-6400型便携式光合仪测定巨尾桉与马尾松、杉木在春季叶片净光合速率（Pn）及其光合生理因子的日变化，并通过相关性分析了解净光合速率与其它光合生理因子的关系。【结果】这3种树种净光合速率在春季均呈现“双峰型”的特点，光合有效辐射（PAR）、气孔导度（Gs）、蒸腾速率（Tr）和胞间CO2浓度是影响这3种树种叶片净光合速率日变化的重要因子。【结论】巨尾桉具有较高的水分利用效率（WUE）、光能利用效率（LUE）和 CO2利用效率（CUE），还具有适应桂林土山生境且生长快速的特性。