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

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.