了哥王叶的结构特征及生态意义

Leaf Anatomic Structure of Wikstroemia indica (L.) C. A. Mey. and Its Ecological Significance

摘要:

运用冷冻切片技术，用光学显微镜对了哥王(Wikstroemia indica (L.) C. A. Mey.)叶的解剖结构进行了观察研究。结果表明，了哥王叶表现出许多旱生、阳生形态，兼具有中生特点。叶表皮由一层排列紧密形状不规则的细胞组成，细胞外壁角质膜较厚；上下表皮均无毛；气孔类型为无规则型，仅分布在下表皮且下陷，气孔密度较小，气孔器面积较大；栅栏组织双栅型，上栅栏组织由1~2层排列整齐的圆柱状细胞组成，下栅栏组织及海绵组织细胞排列疏松，叶肉细胞均含有丰富的叶绿体，栅海比为1.16∶1；主脉发达，具内生维管束和发达的周韧纤维。这些特征反映出了哥王叶片结构与其生长环境相适应。

Abstract:

The leaf anatomic structure of Wikstroemia indica (L.) C. A. Mey was studied under light microscope by using frozen section technique. The results showed that the leaves of W. indica exhibited morphological characteristics of xerophytism, heliophyte with mesophyte. Leaf epidermis consisted of one layer of closely arranged and irregular cells with thick cuticular membrane on outer cell wall, and there were not hair on abaxial and adaxial epidermis. Stomata are anomocytic type, large and sunken, and only sparsely distributed on abaxial epidermis. The two layers of palisade tissue each distributed under the abaxial and adaxial epidermis, respectively. The upper palisade tissue consisted of 1-2 layer(s) regularly arranged cylindrical cells, and the lower palisade tissue and spongy tissue cells arranged loosely, with a ratio of 1.16∶1 for the palisade tissue to the spongy tissue. There were rich chloroplasts in the mesophyll cells. The leaf main vein is well developed with endophytic vasucular bundles and hadrocentric fibers. All these characteristics indicated that the leaf structure of W. indica could well adapt to its growing environment.