应用扫描电子显微镜(SEM)对 15 个黄独(Dioscorea bulbifera L.)居群(11 个野生居群及 4 个栽培居群)植株的叶表皮微形态特征(包括气孔器、表皮毛和气孔周围表皮细胞的特征)进行了观察和测量,并据此编制了 15 个黄独居群的检索表。 观察结果表明:15 个黄独居群植株叶片在气孔器外拱盖内缘类型,气孔器旋转方向,气孔长轴长度及密度和深度,叶片表皮毛的有无及类型,叶肉腺毛的长、短轴长度及密度,气孔周围表皮细胞垂周壁和平周壁的形态以及平周壁表面颗粒形状等特征上均有明显差异。 气孔器外拱盖内缘有光滑和浅波状 2 种类型;气孔器的旋转方向分为不定向旋转、左旋和右旋 3 种方式;气孔长轴长度和密度的变化幅度分别为 18. 59 ~ 31. 93 μm 和86 ~ 356 mm^-2 。 叶片表皮毛均仅存在于下表皮,可分为乳突和多细胞头单细胞柄腺毛 2 种类型,乳突主要分布于主脉,腺毛主要分布于二级脉和叶肉;叶肉腺毛的长、短轴长度的变化幅度分别为 25. 00 ~ 55. 00 和 24. 86 ~ 44. 29μm,大部分居群腺毛密度的变化幅度为 6 ~ 29 mm^-2 。 叶片气孔周围表皮细胞垂周壁的形状有平直、平直隆起、平直脊状隆起、 弯曲、 弯曲脊状隆起和弯曲拱状隆起 6 种类型; 表皮细胞平周壁的表面纹饰有具瘤条纹和光滑条纹2 种形态,其扩散方式也有 2 种形式:一种为不环绕气孔且四方扩散,另一种为环绕气孔 2 ~ 3 周后扩散但扩散方向不定;平周壁上的颗粒形状有簇晶状、屑状、密集粉状、粉状、粒状和片状 6 种类型。 比较分析结果显示:黄独不同居群叶表皮微形态特征的多态性较为丰富,地理分布相近的居群微形态特征的相似性较高,这些特征与黄独的各种下分类群相对应。

 

Micro-morphological characters ( including characters of stomatal apparatus, trichome and epidermal cell around stomata ) of leaf epidermis of Dioscorea bulbifera L. from fifteen populations (including eleven wild populations and four cultivated populations) were observed and measured by scanning electron microscope (SEM), and a key of the fifteen populations was compiled based on micro-morphological characters. The observation results show that there are obvious differences in inner margin type of outer rim and rotation direction of stomatal apparatus, long axis length, density and depth of stomata, with or without trichome and trichome type on leaf, length of long and short axes and density of glandular hair on mesophyll, morphology of anticlinal and periclinal walls and particle shape on periclinal walls of epidermal cells around stomata of leaves among fifteen populations. Inner margins of outer rim of stomatal apparatus have two types of smooth and repand, and their rotation direction contains three types of non-directive, left and right directions. Ranges of long axis length and density of stomata are 18. 59- 31. 93 μm and 86-356 mm^-2, respectively. Trichomes distribute only on lower epidermis with two types of papilla and glandular hair with multicellular head-unicellular stalk, and papilla is mainly on midrib and glandular hair is mainly on sub-vein and mesophyll. Length ranges of long and short axes of glandular hair on mesophyll are 25. 00-55. 00 and 24. 86-44. 29 μm, respectively and its density range is 6-29 mm ^-2 in most populations. Shapes of anticlinal walls of epidermal cells around stomata have six types with straight, straight and projectional, straight and ridgelike projectional, curved, curved and ridgelike projectional, curved and arciform. projectional. Surface ornamentation of periclinal walls of epidermal cells includes two types with tuberculate and smooth stripes and their diffuse modes also contain two modes, one is 4-direction diffusing without surrounding stomata, another is diffusing without definite direction after 2-3 circles of surrounding stomata. And also, particle shapes on periclinal walls contain six types with crystalline cluster, scrap, dense powder, powder, grainy and lamellar. The comparative analysis results reveal that the diversity of micro-morphological characters of leaf epidermis among different populations of D. bulbifera is relatively rich, and populations with close geographic distribution possess higher similarity of micro-morphological characters, which is corresponding to different infra-specific taxa of D. bulbifera.