沉香叶解剖结构的研究

通过石蜡切片法,光学显微镜观察,研究了沉香叶的解剖结构。结果表明,沉香叶为典型的异面叶,但具有许多旱生特征。表皮由一层排列紧密的形状不规则的表皮细胞组成,细胞外壁角质膜较厚,上表皮角质膜较下表皮的厚3.48μm,下表皮上零星分布着单细胞表皮毛,气孔类型为无规则型,仅分布在下表皮上,微下陷;叶肉组织发达,其间分布着较多的长方晶体,其长轴与表皮垂直;栅栏组织由1～2层圆柱形细胞组成,其外层细胞转化为异细胞,栅栏组织∶海面组织为1∶3.5,下表皮内具有1～2层由异细胞组成的下皮层;主脉发达,有异细胞组成的维管束鞘,具内生韧皮部;叶内具有发达的木质部外纤维。以上特征反映出植物结构与环境的统一性。

Study on anatomical structure of leaf of Aquilaria agallocha

The leaf anatomical structure of Aquilaria agallocha Roxb.was studied by using wax-slides and photo-microscopy. The results indicates that the leaf is typical bifacial and has characteristics of xeric in the morphology and the anatomy. Each epidermis consists of a row of irregular epidermic cells which arrange closely,and the horny layer are thick. The horny layers of upper epidermis is 3.48 μm thicker than that of lower epidermis. The sunken stoma only exists in lower epidermis covered by sparse unicellular epidermal hair,and their type is irregular. The mesophyll is very rich. There are many quadrate crystalloids which are perpendicular to the upper epidermis. The palisade tissue is composed of 1～2 layers of cylindrical cells,the outer one of which has translated into idioblasts. The 1～2 layers of hypodermis which consists of idioblasts adjoins to the lower epidermis. The ratio of the palisade tissue to the spongy parenchyma is 1∶3.5. The midrib that is bicollateral bundle is very rich. The bundle sheath consists of idioblasts. There are medullary phloem bundles in midrib. The extraxylary fibres are very rich inside the leaf. The above characteristics of the plant shows that it is adapts to the environment in which they live.