采用石蜡切片法对伞形科鸭儿芹(Cryptotaenia japonica Hassk.)全株不同器官分泌道的结构及分布特征进行了观察研究。 观察结果显示,在鸭儿芹的根、茎、叶和果实各部位均有分泌道,其中果实分泌道特化为油管。 分泌道多由 1 层明显小于周围薄壁细胞的分泌细胞组成,不同器官中分泌道的管腔和分泌细胞均大小不等、形状不一。组成根中分泌道的分泌细胞较少,多为 4 ~ 5 个;茎中较多,为 6 ~ 9 个,有时多达 12 ~ 14 个;组成叶片分泌道的分泌细胞数差异最大,叶脉中多达 22 个,叶肉中仅为 3 个。 从横切面上看,根系中的分泌道仅分布在主根和一级侧根的近周皮处,以及主根的韧皮部外侧和髓部;茎中分泌道分布于近表皮处的厚角组织之间、大厚角组织与韧皮部之间和靠近木质部的髓部;叶鞘和叶柄的分泌道位于小厚角组织内侧的顶端、大厚角组织与韧皮部之间和木质部周围,其中在叶鞘中的 2 个厚角组织之间也有分泌道分布;在叶片的主脉及大侧脉中,分泌道分布于维管束与上下表皮的厚角组织之间,栅栏组织中也有少量分泌道;在果实中,油管分布于内果皮与中果皮之间,多位于棱槽和合生面部位。 此外,根和茎中的分泌道具有 2 种明显不同的分布式样;叶鞘远、近轴面部位分泌道的分布式样分别兼有茎近表皮皮层部位和叶柄维管束木质部部位的特点,具有明显的从茎向叶柄的过渡性;在果实的果棱维管束下方和 2 个油管之间还有 2 层油细胞几乎环果体分布,这种结构在伞形科种类中比较少见,值得进一步研究。

The structure and distribution characters of secretory canals in different organs of Cryptotaenia japonica Hassk. (Apiaceae) were comparatively observed by the paraffin section method. The observation results show that there are secretory canals in root, stem, leaf and mericarp of C. japonica, and the secretory canals specialize to vittaes in mericarp. The secretory canals consist mostly of a layer of secretory cells smaller than the parenchyma cells around them. The lumina and secretory cells of secretory canals in different organs are variant in size and shape. The number of secretory cells in root is mainly 4 - 5, less than that in stem, which is 6 - 9 (sometimes 12 - 14). The number of secretory cells is not the same in different parts of leaf, there are 22 secretory cells in vein but only 3 in mesophyll. The secretory canals in root only distribute in pericycle near the periderm of main root and the first lateral root, as well as in outside the phloem and in pith of main root. In stem, the secretory canals distribute in cortex near the epidermis and regions between the big collenchyma and the phloem, as well as in pith approaching the xylem. The secretory canals in leaf sheath and petiole locate at top of small collenchyma, regions between the collenchyma and the phloem and periphery of the xylem, while there are a few secretory canals between two collenchymas in leaf sheath. The secretory canals of the primary vein and main lateral vein in blade situated in space between collenchyma and vascular bundle, and in the palisade parenchyma of mesophyll. The vittaes distribute between endocarp and mesocarp, mostly in the rib vallecula and on the commissure. In addition, the distribution pattern of secretory canals is obviously different in root and stem. The distribution pattern of secretory canals at the abaxial and adaxial surfaces of leaf sheath combines the characteristics of secretory canals in cortex of stem and in xylem of petiole, respectively, showing the transition from stem to petiole. There are two layers of oil cells under the vascular of mericarp rib and between vittaes, which almost distribute around the mericarp, this structure feature is rare in Apiaceae species and worth further studying.