中国鹅绒藤属(萝藦科)植物叶表皮微形态扫描电镜研究

Studies on the Micromorphology of Leaf Epidermis in Cynanchum (Asclepiadaceae) from China Under Environmental Scanning Electron Microscope (ESEM)

利用环境扫描电镜对13种及1变种分布于中国的鹅绒藤属Cynanchum(萝藦科Asclepiadaceae)植物叶表皮进行观察,以了解鹅绒藤属植物叶表皮细胞轮廓、角质层纹饰、气孔器形状与外拱盖内缘、毛被等特征及其分类学意义.结果表明,鹅绒藤属植物的叶表皮形态具有较高的多态性,而在特定类群中也有相似性,体现在表皮细胞轮廓多为多边形或不规则形,多数种类上表皮气孔不明显,下表皮均有气孔分布,且多数气孔形状为非内陷或浅内陷,气孔外拱盖内缘多为浅波状,上、下表皮均具有较厚角质层,多数种类叶上、下表皮均无毛.叶表皮形态学结果支持将刺瓜C.corymbosum、海南杯冠藤C.insulanum和线叶杯冠藤C.insulanum var.lineare放在同一个组.

The micromorphology of leaf epidermis of 13 species and 1 variety in Cynanchum from China were examined by environmental scanning electron microscope （ESEM）. The results showed that there were high diversity in the micromorphology of leaf epidermis of Cynanchum. The shapes of leaf epidermal cells in Cynanchum were usually polygonal or irregular. All the abaxial epidermis had stomata, and most of the shapes of the stomata were not sunken. The inner margin of the outer stomatal rim was nearly sinuolate. Many species of Cynanchum had glabrous leaves and thick cuticular membrane on leaves. A few species are distinctively different from others in their size of stomata and ornamentation of cuticular membrane. It was accepted to put C. corymbosum, C. insulanum and C. insulanum var. lineare into Section Endotropis.