用透射电镜技术研究了腰果树（AnacardiumoccidentaleL.）末端小枝次生韧皮部分泌道的结构，着重研究了上皮细胞中亲锇物质的形成、积累和排出，这些亲狐物质是分泌道的主要产物．观察表明，在充分发育的上皮细胞中，大量余锇物质出现在细胞质、内质网潴泡和质体中。在细胞质中可以看到大量直径为20～30nm的亲锇的微粒，看来它们能聚集成为大小不等的亲锇物质的团块。这些亲锇物质的团块常常附着在内膜系统上。在高分辨率电镜下，内质网潴泡和细胞质中的亲锇物质团块呈现出髓鞘状结构，它们由紧密堆积的片层状结构组成，在校切面上呈黑白相间的条纹，一个照条纹和一个白条纹的宽度约为5nm．细胞质中的余锇物质的团块被排出上皮细胞之前首先与质膜融合，被分隔至质膜与细胞壁之间，最后通过松散的细胞壁进入分泌沮的腔． Transmission electron microscopy was used to study the structure of part of the phloem of secondary phloem in the terminal branch of Anacardium occidentale L., focusing on the formation, accumulation and excretion of the osmiophilic substances in epithelial cells, which are the main products of the secretory tract. Observations show that in well-developed epithelial cells, a large amount of residual osmium occurs in the cytoplasm, the endoplasmic reticulum, and the plastid. A large number of osmium-osmotic particles of 20-30 nm in diameter can be seen in the cytoplasm. It appears that they can aggregate into clumps of osmiophilic substances of varying sizes. These osmanthus-prone masses are often attached to the intima system. Under high-resolution electron microscopy, the cytoplasm of the endoplasmic reticulum and the osmiophilic mass of cytoplasm showed a myelin-like structure consisting of closely packed lamellar structures with black and white stripes on the school section and a The width of a stripe and a white stripe is about 5 nm. The remnants of the osmanthus mass in the cytoplasm first fuse with the plasma membrane before being expelled from the epithelial cells, separated between the plasma membrane and the cell wall, and finally into the lumen of the secrete chamber through the loose cell wall.