五唇兰两种生态型的光合特性研究

Photosynthetic Characteristics of Doritis pulcherrima Lindl.(Orchidaceae)with Two Ecotypes

以叶背绿色型和叶背紫红型两种五唇兰(Doritis pulcherrima)生态型的组培苗为试材,进行叶片CO2吸收的日动态变化、气孔密度及光合色素的测定进行分析研究。结果表明:五唇兰属于CAM(景天酸代谢途径)植物;叶背绿色型的CO2吸收速率大于叶背紫红型;两种生态型的气孔密度没有显著性差异;两种生态型的总叶绿素含量、叶绿素a(Chl a)含量、叶绿素b(Chl b)含量、叶绿素a与叶绿素b的比值、类胡萝卜素(Car)含量也均没有显著性差异,但胡萝卜素与总叶绿素(Chl)含量的比值则有显著性差异。五唇兰的光合特性及叶片光合色素含量,体现了其作为一种热带兰对生长环境的高度适应性。

Under natural conditions,Doritis pulcherrima presents two kinds of different ecotypes（green and mauve on the leaf dorsal side）.The experiment compared the patterns of CO2 exchange,stomatic density and photosynthetic pigments content in leaves between the two ecotypes a day long.The results showed that Doritis pulcherrima was a CAM plant.Green plants’photosynthetic rate was higher than mauve plants.Stomatic density of the two ecotypes of Doritis pulcherrima was no differences.The chlorophyll a content,chlorophyll b content,total chlorophyll content and chlorophyll a/b value of green plants were little higher than that of mauve plants.However,Carotenoid content of the mauve plants was little higher than that of the green plants.The ratio of carotenoid content/total chlorophyll content was significantly higher in the mauve plants than that in the green plants（p〈0.01）.The leaf anatomy structure and photosynthetic characteristics indicated that the Doritis pulcherrima,which identified as a tropical orchid,had great adaptation to their growing habitats.