兰属、兜兰属、石斛属植物叶片的扫描电镜观察

对兰科植物的兰属、兜兰属及石斛属１６个种折叶片及其横断面进行了扫描电镜的观察。兰属各种叶片上表皮细胞均为矩形，上表皮细胞表面具小乳突或不明显突起。石斛属及兜兰属的各个种上下表皮细胞均为多边形，但石斛属表皮细胞表面无坦无纹饰，而兜兰属花叶类上表皮细胞表面明显呈乳突状，绿叶类呈龟背状隆起。兰属及石斛属叶片叶肉组织没有栅栏组织及海绵组织的分化，而兜兰属的绿叶类叶肉不分化；花叶类叶肉有分化。

INVESTIGAIONS ON LEAVES OF CYMBIDIUM,PAPHIOPEDILUM,DENDROBIUM UNDER SCANNING ELECTRON MICROSCOPE

The morphological characters of leaves on 16 species in Cymbidium,Paphiopedilum and Dedrobium were investigated under SEM.There are different characters of epidermis on leaves in the three genera.The cells of upper and lower epidermis are rectangular and the surfaces of cells are glandular protrusions in Cymbidium.The cells of ventral and dorsal epidermises in leaves are polygonal both in Dendrobium and Paphiopedilum.Papillae or protrusions occur on surfaces of the ventral epidermal cells in Paphiopedilum.But the surfaces of ventral epidermal cells are flat without ornamentation in Dendrobium.Palisade tissue is absent in the leaf mesophyll of species investigated in Cymbidium and Dendrobium.It is also absent in that of species with green leaves, but present in that of species with white streaks or spots at leaf adacial surface in Paphiopedilum.