三种国产阴地蕨科植物叶的表皮构造

The Leaf Epidermal Structures of Three Species of Botrychiaceae from China

运用光学显微镜和扫描电镜对三种国产阴地蕨科植物 :劲直蕨萁 (Botrypusstrictus)、小阴地蕨(Botrychiumlunaria)和薄叶阴地蕨 (Sceptridiumdaucifolium)叶的成熟表皮构造进行了详细观察和研究。它们具有共同的特征 :气孔散生 ,气孔类型无规则型 ,气孔长轴方向多与叶脉延伸方向一致。但也存在明显区别 ,特别是劲直蕨萁与另外二个种的区别更为明显 :前者表皮细胞垂周壁直 ,相邻气孔不接触 ,保卫细胞平周壁具细条纹。但后二者之间亦有一定区别 :薄叶阴地蕨的气孔为下生式 ,不下陷 ,而小阴地蕨的气孔为两面气孔型 ,气孔下陷。本文是国内首次对阴地蕨科叶的表皮构造进行研究 ,其研究结果表明 ,表皮构造在阴地蕨科植物的鉴定上具有重要意义 ,并且在研究阴地蕨科的分类以及起源和演化上也有一定参考价值。

Up to now, a lot of papers on the epidermal structures of ferns have been published in the world. But in China, few people have paid attention to this work. The epidermal structures of three species, Botrypus strictus, Sceptridium daucifolium and Botrychium lunaria, are studied by the observation with optical and scanning electronic microscopy. The description comprises the cuticle thickness, the epidermal cells, the distributions of stomata, the stomatal orientation, structures, types, frequencies and index etc.. They have common characteristics in the stomatal orientation and types, but are different in the epidermal cells, the stomatal distribution, size, frequencies, index etc. The study presents new evidences to the identification of the three species. The main diagnoses of the epidermal structures of the three species are as follows: (1) Botrypus strictus: The epidermal cell wall wavy or deeply sinuous. Stomata confined to the lower epidermis and scattered in the interveins and on the veins. Some of the stomata closely situated and the guard cells contacted with each other. Stomata elliptical in shape with their long axes parallel to the lamina or the veins. The stoma consisting of two lens_like guard cells, 44～53 μm×11～17 μm in size, with smooth inner and outer periclinal walls. 6～7(occationally 8 or 9) neighbouring cells sur_ rounding each stoma. 32～35 stomata in each mm 2. Stomatal index 5.6. (2) Sceptridium dauci_ folium: The epidermal cell wall straight. Stomata confined to the lower epidermis, scattered in the interveins. Stomata anomocytic, narrowly elliptical in shape, with their long axes parallell to the lamina or veins. Guard cells reniformis in shape and 76～95 μm×17～23 μm in size, with concentric stripes on the inner surface of outer periclinal wall. 6～8(occationally up to 9) neighbouring cells surrounding each stoma. 14～19 stomata in each mm 2. Stomatal index 6.7～7.2. (3) Botrychium lunaria: The epidermal cell wall straight. Stomata distributed on the upper and lower epidermis, scattered. The stamata anomocytic, elliptical to round in shape, with their long axes parallel to the lamina or veins. Guard cells reniformis in shape, 48～65 μm×15～23 μm in size with concentric stripes on the outer and inner surfaces of outer periclinal wall. 5～7 (mostly 6) neighbouring cells surrounding each stoma. 23～29 stomata in each mm 2. Stomatal index 6.7.