薯蓣属根状茎的组织结构和萆薢类药材鉴别

应用显微镜观察了中国薯蓣属根状茎组17种1亚种1变种根状茎组织结构。结果显示,(1)根状茎均由周皮、内外侧基本组织和散生维管束组成;(2)木栓层外方常见被挤压或残留的基本组织薄壁细胞,并有木化厚壁细胞及石细胞;外侧基本组织含有散生或稀疏排列成环的粘液细胞(含草酸钙针晶束);内侧基本组织占广大部位,薄壁细胞愈近中央部位的愈大,维管束绝大部分外韧型,无形成层;(3)木质部有大型管胞或导管,管壁孔纹或网纹增厚,大形筛管易见,导管多短节状,显示了演化上的原始性;淀粉粒形态结构多样。结果表明,薯蓣属根状茎组织结构特点可作为分类依据,并显示了该组为一个自然类群。其中,药材粉萆薢(粉背薯蓣、叉蕊薯蓣)、绵萆薢(绵萆薢、福州薯蓣)的原植物根茎组织结构具有明显的鉴别意义。

Tissue Structures of Dioscorea Rhizomes and Authentication of Rhizoma Dioscoreae Hypoglaueae Medicinal Materials

The rhizome tissue structures of 17 species,one subspecies and one variety of Dioscorea were observed by microscopy.It was shown that(1) all the rhizomes were composed of periderm,inner and outer ground tissues and scattered vascular bundles;(2) Pressed or residual parenchymatous cells of the ground tissues could be seen to stand with lignified sclerenchymatous cells and sclereids outside the phellem,the outer ground tissues took most space,the parenchymatous cells became larger in size as they lain closer toward the central part and most of the vascular bundles were collateral vascular bundles and contained no cambiums;(3) In the xylem,there were large tracheids or vessels with thickened wall pits or ornamentations and large easily visible sieve tubes and the vessels had nodous appearance,which indicated the primitiveness in sect.Stenophora evolution;the starch grains and structures were diverse.These results showed that the tissue-structure characters of Dioscorea rhizomes could be used as taxonomical criteria and sect.Stenophora was a natural goup as well.Herein,the tissue structures of Fenbixie rhizome of D.collettii var.hypoglauca(Palibin) Pei et Ting and D.collettii Hook.] and Mian Bixie(rhizome of D.septemloba Thunb.and D.futschauensis Uline ex R.Knuth) were of remarkable significance in their authentication.