瘤足蕨科及其近缘类群植物叶表皮微形态扫描电镜观察

Micromorphology of leaf epidermis in Plagiogyriaceae and its related taxa under SEM

关键词:  瘤足蕨科, 桫椤科, 蚌壳蕨科, 叶表皮, 扫描电子显微镜

Key words:  Plagiogyriaceae, Cyatheaceae, Dicksoniaceae, leaf epidermis, scanning electron microscope

摘要:

瘤足蕨科是一个自然的群,但由于各类群之间的形态差异及种内变异比较大,其分类和系统位置一直有争议。该研究利用扫描电子显微镜对瘤足蕨科10种及其近缘类群桫椤科2种、蚌壳蕨科1种共13种植物,即瘤足蕨(Plagiogyria adnata)、耳形瘤足蕨(P. stenoptera)、镰羽瘤足蕨(P. falcata)、峨嵋瘤足蕨(P.assurgens)、密羽瘤足蕨(P. pycnophylla)、灰背瘤足蕨(P. glauca)、华东瘤足蕨(P. japonica)、华中瘤足蕨(P. euphlebia)、日本瘤足蕨(P. matsumureana)、美洲瘤足蕨(P. pectinata)、桫椤(Alsophila spinulosa)、西亚黑桫椤(A. khasyana)和金毛狗(Cibotium barometz)的叶表皮微形态进行了观察和比较,探讨其分类学意义,并据此编制了供试10个种类的分类检索表。结果表明:13种瘤足蕨科及其近缘类群植物气孔均仅分布在叶下表皮,气孔微下陷,气孔器椭圆形至圆形; 叶上下表皮角质层纹饰复杂,类型多样,少数类群叶下表皮具毛状物; 多数类群气孔外拱盖凹陷; 气孔外拱盖内缘浅波状或齿状; 保卫细胞两极大多数有明显的“T”型加厚。不同种间叶表皮扫描电镜特征表现出一定差异,对种的划分有一定的分类学鉴定意义。

Abstract:

Plagiogyriaceae is a natural fern group with some classification and systmatics controversy because of more morphological differences exist infra and interspecies. The leaf epidermises of ten species of Plagiogyriaceae: Plagiogyria adnata, P. stenoptera, P. falcata, P. assurgens, P. pycnophylla, P. glauca, P. japonica, P. euphlebia, P. matsumureana and P. pectinata, and two species of Cyatheaceae(Alsophila spinulosa and A. khasyana)and one species of Dicksoniaceae(Cibotium barometz)of its related taxa were observed and compared by scanning electron microscope(SEM), and its taxonomical significance was discussed. Hereby, key to ten species tested was also compiled. The stomatal apparatus were oval to circular and restricted in abaxial epidermises for all species. The cuticular membrane of the adaxial leaf epidermis was complicated and some hairs in abaxial epidermis. The patterns of anticlinal walls were depressed. The inner margin of the outer stomatal rim was often sinuous and odontoid, and “T” shape, upright outer stomatal rims occurred in most species. The microcharacters of leaf epidermises can be used as evidence for the classification of the interspecies in Plagiogyriaceae.