雌雄异株树种山杨、水曲柳和东北红豆杉光合特性对比

【目的】探究雌雄异株树种的光合生理生态特性，为正确评价其对环境的适应机制以及确定影响种群建成的因素提供理论参考。【方法】以野外成树为研究对象，通过Li-6400XT便携式光合作用测定仪对比分析了山杨(Populus davidiana)、水曲柳(Fraxinus mandshurica)和东北红豆杉(Taxus cuspidata)雌雄株叶片气体交换参数。【结果】3个树种整体上雌株光合特性优于雄株，雌雄株参数仅在山杨光补偿点(P_LCP)和最大羧化速率(C_E,max),水曲柳水分利用效率(E_WUE),东北红豆杉光饱和点(P_LSP)、光补偿点、羧化效率(C_E)和光呼吸速率(R_p)之间差异显著(P<0.05)。另外，雌株的叶性状指标并不低于雄株的。【结论】3个树种雌株较优的光合特性可能存在获取资源的补偿机制，以同时满足营养生长和生殖生长的生存需求。

Photosynthetic characteristics of dioecious Populus davidiana,Fraxinus mandshurica and Taxus cuspidata

【Objective】 Exploring the photosynthetic characteristics of both sexes is valuable for additional assessment of environmental adaptation mechanisms and population formation in dioecious tree species.【Method】In the present study, the leaf photosynthetic gas exchange parameters of adult females and males of Populus davidiana, Fraxinus mandshurica and Taxus cuspidata were measured using a Li-6400XT portable photosynthesis system. 【Result】 Three female tree species consistently presented superior photosynthetic properties than the opposite sex even though significant differences were only observed at the light compensation point (P_LCP) and maximum carboxylation rate (C_E,max) of P. davidiana, water use efficiency (E_WUE) of F. mandshurica, and at the light saturation/compensation point (P_LSP/P_LCP), carboxylation efficiency (C_E), and light respiration rate (R_p) of T. cuspidata between genders. Leaf traits parameters for three female tree species exhibited a non-significant trend with higher values than those of males. 【Conclusion】 These results indicate that the three female tree species with higher photosynthetic capacity may exhibit compensatory mechanisms for simultaneously maintaining vegetative and reproductive growth to maximize lifetime fitness.