美洲鳄梨属植物的叶表皮微形态特征及其分类学意义

Micro-morphological Characteristics of Leaf Epidermis under Light Microscopy and Its Taxonomic Significance in Persea(Lauraceae) from America

在光学显微镜下,对美洲鳄梨属54种植物的叶表皮微形态特征进行了观察,研究发现叶表皮细胞形状多为规则形;垂周壁一般平直;大多数种类的叶表皮具均匀分布的单细胞毛状体;平列型气孔器下生,随机分布于网状叶隙内,可进一步分为3个小类;形态相似的物种通常具有相似的叶表皮特征。本研究选取了19个特征进行PCA分析,发现鳄梨属被明显分为2个支系。叶表皮特征在种内比较稳定,种间存在一定差异,表皮细胞形状、气孔器形态及其突出物等特征组合对于鳄梨属种尤其一些表型相似的种类的鉴定有一定的帮助。

Leaf epidermal micro-morphological characters of 54 species belonging to genus Persea （Lauraceae） from America were comparatively studied by the means of light microscopy. It was shown that the leaf epidermal cells were usually regular bearing with straight or beaded anticlinal walls.Most of these species had unicellular trichomes uniformly distributed. The stomatal apparatus which were paracytic,only randomly presented in the areoles of abaxial epidermis for all sampled species,can be assigned into three types. The results showed that similar leaf epidermal characters can be found in the species with similar morphology. Nineteen characters were selected for PCA analysis,and the sampled species was divided into two clades. The characters of leaf epidermis were little different within a species but can vary among species. However,the multiple leaf epidermal characters including the shape of epidermal cells,the shape of stomatal apparatus,stomatal ledges and some distinct characters were relatively constant and taxonomically quite useful for the identification of some species with similar phenotypes.