西藏东达山3种嵩草属植物叶片解剖结构的比较

Comparison of Leaf Anatomical Structure of 3 Species of Kobresia in the Dongda Mountains, Tibet

  • 摘要: 为研究3种嵩草属植物叶片形态解剖特征,采用石蜡切片法,分析叶片表皮、叶肉、叶脉等解剖结构的差异,并比较分析叶片不同部位的解剖结构特征。结果表明:3种嵩属草植物叶表皮近、远轴面均由1层表皮细胞组成,线叶嵩草表皮细胞最大,其次为高山嵩草,大花嵩草最小。大花嵩草近轴面主脉凹陷处存在泡状细胞,高山嵩草和线叶嵩草近轴面无泡状细胞。3种嵩草叶表皮均具有较厚的角质层,近轴面角质层均厚于远轴面,线叶嵩草角质层最厚,其次是高山嵩草,大花嵩草最薄。叶肉没有栅栏组织与海绵组织的分化,但有发达的气腔。机械组织和维管束占叶片横切面面积的比例均较小,线叶嵩草最大,高山嵩草次之,大花嵩草最小。线叶嵩草维管束鞘总面积最大,高山嵩草次之,大花嵩草最小。3种嵩草属植物叶片不同部位解剖结构均存在差异,其中高山嵩草在叶片不同部位中存在极显著差异的结构最多,线叶嵩草次之,大花嵩草最少。可见,3种嵩草植物叶片解剖结构差异显著,可以作为分类学的重要依据;均具有典型的旱生植物特点,线叶嵩草和高山嵩草有较厚的角质层,而大花嵩草通过较小的表皮细胞和泡状细胞响应生境干旱化。

     

    Abstract: In order to study the morphological and anatomical features of the leaves of 3 species of Kobresia, paraffin sectioning was used to analyze the differences in anatomical structures such as leaf epidermis, mesophyll and veins, and to analyze the anatomical features of different parts of the leaves. The results show that the near and far axis of the leaf epidermis of 3 species of Kobresia are composed of 1 layer of epidermal cells. The epidermal cells of K. capillifolia are the largest, followed by K. pygmaea, and the smallest of K. macrantha. There are vesicular cells in the main vein depression of K. macrantha, and the sacral cells of the subalpine surface of K. pygmaea. Three species of Kobresia leaves have thicker stratum corneum, the paraxial stratum corneum is thicker than the abaxial surface, and the K. capillifolia is the thickest, followed by K. pygmaea and the thinnest of K. macrantha. The mesophyll has no differentiation of palisade tissue and sponge tissue, but has a developed air cavity. The ratio of mechanical tissue and vascular bundles to the cross-sectional area of the leaves is small, and K. capillifolia is the largest, the K. pygmaea is the second, and K. macrantha is the smallest. The total area of vascular bundles of K. capillifolia is the largest, followed by K. pygmaea, and the smallest of K. macrantha. There are differences in the anatomical structures of different parts of the leaves of 3 species of Kobresia. Among them, K. pygmaea has the most significant difference in the different parts of the leaves, followed by K. capillifolia, and the least is K. macrantha. It can be seen that the anatomical structures of the leaves of the three species of Kobresia are significantly different and can be used as an important basis for taxonomy. They all have typical characteristics of xerophytes. K. capillifolia and K. pygmaea have thicker stratum corneum, while K. macrantha responds to habitat aridification through smaller epidermal cells and vesicular cells.

     

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