慈菇匍匐茎中分泌道的初步研究

慈茹匍蔔茎的分泌道是裂生的胞间道,分布于匍匐茎的基本组织中。单个分泌道原始细胞起始于离茎端约1毫米处的基本分生组织中,原始细胞经分裂形成5—7个上皮细胞包围着中央的裂生腔隙,成为管道系统。上皮细胞无鞘细胞包围。上皮细胞中高尔基体和内质网发达,并溢出小囊泡向着分泌道腔隙面壁的质膜附近迁移,乳汁中亦存在大量完整的小囊泡。上皮细胞和外围薄壁细胞之间的壁层具有大量胞间连丝,小囊泡和内质网的膜结构与胞间连丝末端相接,同时可见上皮细胞的质膜在数处反折内陷,形成袋状结构,在与上皮细胞相对的薄壁细胞内也有同样现象出现,袋状结构内含小形颗粒或囊泡,并在结构上显示出上皮细胞与相邻薄壁细胞间存在着活跃的物质交流。由此认为。代谢物质以整体小囊泡的形式经胞间连丝或内陷的质膜向分泌道迁移是物质运输和分泌的可能方式之一。在电镜下观察,液泡中的积聚物与乳汁十分相似,液泡可能是乳汁的贮存场所之一。

A PRELIMINARY STUDY ON THE SECRETORY DUCTS OF THE STOLON OF SAGITTARIA SAGITTIFOLlA L.

Schizogenous secretory ducts are found in the ground tissue of the stolon of Sagittaria sagittifolia L. The single secretory duct initial develops from the ground meristem at the level 1 millimeter from the shoot apex. By successive divisions of the initial cell, 6-8 epithelial cells are formed with a schizogenous cavity at their center which forms the lumen of the secretory duct. No sheath cells are found outside the epithelial cells. Ultrastructural study of the epithelial cells reveals that a lot of vesicles are spilled by the Golgi apparatus and endoplasmic reticulum which remove towards the lumen and gather nearby the side of plasm alemma. Such vesicles can also be found in the latex. plasmodesmata occur in the cell wall in between the epithelial cells ahd their surrounding parenchymatous cells. Membrane structure of vesicles and endoplasmic reticulum are found in connection with plasmalemma. In the meanwhile, pocket like structures forming by invagination of plasmalemma are frequently observed singly or in pair by the side of secretory epitheium and secretory duct and secretory epithelium and parenchyma cell respectively. Vesicles occur in such structure. All these facts indicate that active compound exchange is carrying out structurally in between the epithelial cells and their surrounding parenchyma cells. It leads to the assumption that metabolite/or secretion is removed through endoplasmic reticulum or invaginated plasmalemma to the secretory duct in the form of small vesicles. Electron Microscopy shows that the contents in the vacuoles are the same to that of the latex, and it is probable that vacuoles may be one of the sites for latex storage.