白木香[Aquilaria sinensis(Lour.)Gilg]的木质部结构及组织化学研究

利用离析技术、显微观察和组织化学鉴定等方法,对白木香的木质部结构及组织化学进行了研究。结果表明,木质部由5部分组成:髓心、内涵韧皮部、木射线、导管、纤维管胞。内涵韧皮部呈多孔型均匀分布;木射线单列(双列少见)异型Ⅲ;管孔排列为径向管孔团、复管孔、管孔链和单管孔;导管侧壁有互列纹孔式和附物纹孔;纤维管胞侧壁有单斜附物纹孔;径列条及栓塞首次在白木香中发现;进一步证实淀粉、还原性糖和挥发性成分在不同年龄的木质部里含量及储存部位存在差异。本研究为沉香的形成提供基本的解剖学证据。

Study on xylem structure and histochemistry in Aquilaria sinensis

To study the morphological and quantitative characteristics of the xylem and histochemistry of different-aged stems in Aquilaria sinensis,the anatomical structure of the stem was analyzed using the Jeffery method,histochemical staining,and microscopic observation.The results showed that the xylem was composed of 5 parts: pith,included phloem,xylem rays,vessels,and fiber tracheids.A transverse section showed that the included phloem(foraminate type) evenly distributed in the xylem.The xylem rays belonged to heterogeneous Ⅲ.The vessel pores were generally arranged as follows: radial pore clusters(2 to 4),multiple pores,pore chains(5 to 10),or a single pore;vestured pits were alternately arranged in the vessels′ lateral walls.Acclivitous simple vestured pits were present in the lateral walls of the fiber tracheid.Trabeculae were present in the neighboring fiber tracheids of the pith.Embolisms were present in the vessels and the fiber tracheids.Trabeculae and embolisms were firstly observed in A.sinensis.The levels and storage tissues of starch,reducing sugars,and volatile constituents were significantly different in the different-aged xylem.This study provides basic anatomical evidence for agarwood formation.