齿瓣石斛光合特性研究

Study of Photosynthetic Characteristics of Dendrobium devonianum

石斛（Dendrobium SW．）为兰科（Orchidaceae）多年生草本植物，常附生于温暖湿润半荫环境下的树干或岩石上，生长缓慢，是我国传统名贵中药。目前发现的石斛属植物有1500多种，主要分布在亚洲热带和太平洋岛屿的东亚、东南亚及澳大利亚等地区。

In order to study the photosynthetic characteristics of Dendrobium devonianum, the diurnal dynamics of photosynthesis and the response of photosynthetic rate to photosynthetic active radiation and CO2 were analyzed by LI-6400 portable photosynthesis analysis system under overshadow conditions. The results showed ： （ 1 ） The diurnal variation of D. devonianum followed a double-peaks curve, there was obvious midday depression of photosynthesis. （2） The change rule of the response of photosynthetic rate to photosynthetic effective radiation and CO2 were simi- lar, the critical points of light compensation and saturation of D. devonianum were 4. 4 and 182. 5 μmol · m^-2 · s^-1 , respectively; the apparent quantum efficiency was 0. 03 mol · mol^-1 Its CO2 compensation point and satura-tion point were 162.5 and 1 240. 25 μmol · m^-2 ·s^-1, respectively; its carboxylation efficiency was 0. 004. （3） D. devonianum, as the same as other Dendrobium plants, belong to shade plants, therefore, shading and tempera-ture and humidity controlling are needed in the cultivation and management.