广东省林业科技创新专项（2011KJCX002, 2012KJCX002, 2013KJCX002）
【目的】揭示我国特有的速生优质用材树种香椿Toona sinensis种源间光合特性的差异，为优良种源的选择提供依据。【方法】对11省14县（市、区）的1年生香椿种源苗木5个瞬时光合生理指标进行Li-6400测定和分析。【结果】净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、蒸腾速率（Tr）、水分利用效率（WUE）5个指标在种源间存在极显著差异。其中，Gs变异系数最大，Ci变异系数最小，分别为27.52%、4.24%。各指标的重复力以Pn最高，WUE最低，分别为96.08%、78.52%。Pn与Gs、Tr、苗高呈极显著正相关(P<0.01)，与地径呈显著正相关(P<0.05)；Gs与Ci、Tr、苗高呈极显著正相关(P<0.01)，Ci与Tr呈显著正相关(P<0.05)，Tr与苗高呈极显著正相关(P<0.01)，与地径呈显著正相关(P<0.05)。广西兴安、广西那坡、四川蓬安种源的Pn较大，广西兴安、广东乐昌种源的WUE较大。【结论】对5个指标进行主成分分析，得到2个主成分，可以把14个香椿种源分为3类：光合参数中蒸腾速率最小; 光合速率和水分利用效率都较高; 光合作用较强和水分利用效率较低。
【Objective】Toona sinensis is a China endemic timber species of high quality and fast growth. This study was aimed at investigating differences in photosynthetic characteristics among different T. sinensis provenances, and providing a theoretical basis for selection of superior provenances.【Method】Five photosynthetic indices of one-year-old seedlings of T. sinensis provenances collected from 14 counties in 11 provinces were measured with Li-6400 and analyzed. 【Result】There were highly significant differences among different provenances in five photosynthetic indices including net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) and water use efficiency (WUE). The variation coefficient of Gs was the highest (27.52%), and that of Ci was the lowest (4.24%). The repeatability of Pn was the highest (96.08%), and that of WUE was the lowest (78.52%). Pn was highly significantly positively correlated with Gs, Tr and seedling height (P<0.01), and significantly positively correlated with ground diameter (P<0.05). Gs was highly significantly positively correlated with Ci, Tr and seedling height (P<0.01). Ci was significantly positively correlated with Tr (P<0.05). Tr was highly significantly positively correlated with seedling height (P<0.01) and significantly positively correlated with ground diameter (P<0.05). Provenances collected from Xing’an and Napo of Guangxi Province, and Peng’an of Sichuan Province had relatively high Pn compared to those from other counties, and provenances from Xing’an of Guangxi Province and Lechang of Guangdong Province had relatively high WUE.【Conclusion】Two principal components were obtained from five tested indices using the principal component analysis. Fourteen T. sinensis provenances can be divided into three groups including the group with the lowest Tr, the group with relatively high Pn and WUE, and the group with relatively strong photosynthesis and low WUE.