中文摘要：

【目的】探索美洲商陆入侵的生理生态机制以及与其伴生种在能量、水分、氮素等资源利用效率方面存在的优势,为美洲商陆的风险评价和综合防控提供参考。【方法】利用TPS-1光合系统测定林缘高光照和林下低光照环境下生长的美洲商陆及其伴生种紫穗槐的光合性能参数,并根据相关参数计算光能利用率和水分利用率。采用Handy-PEA植物效率仪测定其荧光参数;Vario Micro cube元素分析仪测定叶片全氮含量;C2000氧弹热量计测定干质量热值,并由此计算叶片光合氮利用效率和建成成本。【结果】在林缘高光照和林下低光照环境下,美洲商陆的表观光量子效率、最大净光合速率、叶绿素含量、光系统II最大光化学效率（F_v/F_m）和以吸收光能为基础的性能指数（PIABS）均显著高于其伴生种紫穗槐（P〈0.05）,而光补偿点和叶绿素a/b比值则显著低于紫穗槐（P〈0.05）。美洲商陆光能利用率和光合氮利用效率也是显著高于紫穗槐（P〈0.05）,水分利用率在高光照条件下美洲商陆低于紫穗槐、在低光照条件下则是美洲商陆高于紫穗槐。在高光照和低光照环境下,美洲商陆的叶片单位质量建成成本（CC_（mass））和单位面积建成成本（CC_（area））均显著低于其伴生种紫穗槐（P〈0.05）。同时,在林下低光照环境下,美洲商陆和紫穗槐的光合性能指标、资源利用效率指标和叶片建成成本的差异率均大于林缘高光照环境下的差异率。这说明在低光照资源环境下,美洲商陆的光合能力、资源利用效率和物质、能量利用策略更具优势。【结论】美洲商陆与其伴生种相比具有更高的光合能力、更高效的资源利用效率和更低的构建自体的成本（物质和能量）消耗,这使其具有高生长速率和较强竞争力。特别是在光能资源不足的林下低光照环境下,美洲商陆更具竞争优势。

英文摘要：

【Objective】Pokeweed（ Phytolacca americana） is an invasive plant specie sand now widely distributed in China.This paper explores the ecophysiological mechanism of pokeweed invasion and its advantages over the accompanying species in terms of their energy use efficiency,and usage of water,nitrogen and other resources,in order to provide a reference for risk assessment of pokeweed and the comprehensive prevention and control.【Method 】 This experiment was performed in the coastal protection forest belt in northern Yantai.In this study,the photosynthetic performance parameters of pokeweed and its accompanying species Amorpha fruticosa at the margins of the forest were measured with a TPS-1 photosynthetic system under both low and high light environment to study the ecophysiological mechanism of invasion.Light use efficiency and water use efficiency were calculated according to the related parameters.The chlorophyll fluorescence parameters were detected by using a Handy-PEA system.The total nitrogen content of leaves was analysed with the vario Micro cube element analyzer.The gross calorific value was evaluated with a C2000 oxygen bomb calorimeter,and the leaf photosynthetic nitrogen use efficiency and construction cost were thus calculated.【Result】Under both high and low light conditions,the apparent quantum efficiency（ AQY）,maximum net photosynthetic rate（ Pmax）,chlorophyll content,maximum quantum efficiency of photosystemⅡ（F_v/ F_m） and photosynthetic performance index on energy absorption basis（ PIABS） in pokeweed were significantly higher than those of its accompanying species A.fruticosa（P〈0.05）.However,the light compensation point and chlorophyll a/b ratio were significantly lower than those in A.fruticosa（P〈0.05）.The Light use efficiency（LUE）,and photosynthetic nitrogen-use efficiency（PNUE） in pokeweed were significantly higher than those in A.fruticosa（P〈0.05）; the water use efficiency（WUE） of pokeweed was lower than that in A.fruticosa under high