杜鹃花属5种植物叶表皮结构解剖及分类意义初探

Leaf Epidermal Features and their Taxonomic Significance of Five Species of Rhododendron in China

利用光学显微镜(LM)和环境扫描电子显微镜(SEM)对杜鹃花属(Rhododendron)马银花亚属(Azaleatrum)5种分类争议较大的刺毛杜鹃(R.championiae Hook.)、弯蒴杜鹃(R.henryi Hance)、东南杜鹃(R.dunnii Wils.)、毛棉杜鹃(R.moulmainense Hook.)、凯里杜鹃(R.westlandii Hemsl.)的叶表皮特征进行观察.结果表明叶表皮的细胞形状大小、表皮毛和气孔器具有一定的分类学意义.根据5个种的叶表皮毛被的过渡性,结合花部形态,东南杜鹃和弯蒴杜鹃更接近于凯里杜鹃,初步推测东南杜鹃和弯蒴杜鹃为毛棉杜鹃与凯里杜鹃的天然杂交种.弯蒴杜鹃与东南杜鹃的叶表皮毛被数量和气孔器周围环状条纹存在明显差异,支持东南杜鹃作为独立的种.

Micromorphological characteristics of leaf epidermis of Rhododendron championiae Hook.,R.henryi Hance,R.dunnii Wils.,R.moulmainense Hook.,and R.westlandii Hemsl.were observed and described under light microscopy（LM） and scanning electron microscopy（SEM）.The results showed that the shape and size,scale,gland,trichomes and stomatal apparatus of the leaf epidermis varied with the five species and these characteristics could be used to identify the species of Rhododendron.It was speculated that R.henryi and R.dunnii were the natural hybrid species between Rhododendron championiae and R.westlandii.There were some transitional variations of the trichomes among the five species and the floral characteristics of R.henryi and R.dunnii were more similar to R.westlandii.Besides,the foliar trichomes and stomatal apparatus displayed a marked difference between R.henryi and R.dunnii.This result supported that R.dunnii was an independent species but not the subspecies of R.henryi.