臭椿茎中分泌道的发育及其组织化学研究

利用植物解剖学方法研究臭椿茎和叶柄中分泌道的结构、分布和发育过程.结果表明:臭椿茎和叶柄中的分泌道分布于髓的周缘,次生木质部中无分泌道.分泌道是由一层分泌细胞围绕分泌腔而构成,分泌细胞外有1～2层鞘细胞.分泌道以裂生方式形成,其发育过程可分为3个阶段:原始细胞阶段、形成阶段和成熟阶段.在原始细胞阶段,一群原始细胞具浓厚细胞质,细胞核清晰可见;形成阶段,原始细胞的中央细胞间细胞壁中层降解,细胞壁分离,形成腔隙,随着分泌细胞数量的增加,分泌腔体积扩大;成熟阶段的分泌道具有12～16个分泌细胞,1～2层鞘细胞,分泌腔直径为30～50μm.组织化学研究表明,分泌细胞及分泌道内含物中含大量的萜类、多糖和脂类物质.机械创伤能够诱导次生木质部中产生创伤分泌道.臭椿茎中的分泌道和创伤性分泌道在抵御生物和非生物胁迫中起重要作用.

Development and Cytochemistry of Secretory Ducts in Ailanthus altissima

The distribution,development and anatomy of secretory ducts were studied with anatomical methods in Ailanthus altissima,an important plant of family Simaroubaceae.The secretory ducts are normally present in petiole and stems.In stem and petiole,secretory duct occur in the peipheral region of the pith.The ducts are formed by the separation of epithelial cells from each other during development,surrounded by 1～2 layers of sheath cells.Ducts develop schizogenously in the stem and three developmental stages have been divided:original cell stage,formation stage and maturation stage.At the original stage,cell had dense cytoplasm and clearly visible nucleus;At the formation stage,the number of secretory cells and the secretory lumen increased significantly;At the maturation stage,the secretory duct with 12 to 16 secretory cells,1～2 layers of sheath cells,duct diameter about 30～50 μm.Cytochemical test reveals that the normal ducts consist of terpenoids,polysaccharides and resins.Traumatic ducts are also arising under the stimulus of mechanical wounding,in the xylem of stems.In Ailanthus altissima,the secretory ducts and traumatic secretory ducts play an important role in botic and abotic stress.