Abstract: An anatomical study on the stems of Vanilla planifolia and V.siamensis was made recently and the result showed that the arrangement and structure of stem tissues of these two species were different.In the cross section of the stem of V.planifolia,there is an annular sclerenchyma composed of some particular cells which are small and with sepcialized and thick walls between cortex and vascular tissue region.But in the stem of V.siamensis,this not only the important anatomical character to distinguish the two species,but also has potential value in the study of hybridization and breeding between the two species.

Key words: Vanilla, Stem, Anatomical characters

摘要： 对引自墨西哥的香荚兰Vanilla planifolia Andr．和生长于云南河口县城附近沟谷雨林下的滇南香荚兰 V．siamensis Rolfe ex Downie进行了茎的解剖研究。结果表明，两者在茎的解剖特征上有显著差异。从茎的横切面上看，引自墨西哥的香荚兰，在皮层最内方与维管区之间存在一环带状的厚壁组织，而滇南香荚兰茎则没有形成这种厚壁组织环；香荚兰茎的皮层细胞小，易于与维管区域的薄壁组织细胞相区别，而滇南香荚兰茎的皮层细胞较大，难与维管区域的薄壁组织细胞区分开来。在同属不同种植物茎中存在如此大的解剖学特征差异实属罕见。它不仅为区分这两个种提供重要的解剖特征依据，而且对于开展种间杂交和对杂种后代的识别具有指导意义。

关键词: 香荚兰属, 茎, 解剖学特征