绞股蓝营养器官的结构及其人参皂甙的组织化学定位研究

Anatomical structure of vegetative organs and histochemical localization of ginsenosides in Gynostemma pentaphyllum

绞股蓝是多年生草质藤本植物。根系由不定根组成 ,根的初生结构木质部为 2～ 4原型 ,次生结构中栓内层较厚。攀缘茎 ,具 5棱 ,周围纤维连成一环 ,幼茎的维管束排成两圈 ,外圈 5个 ,内圈 4或 5个 ;老茎圆柱形 ,周围纤维呈不连续环状 ,维管束具次生木质部和次生韧皮部 ,排成一圈。掌状复叶互生 ,小叶 5～ 7片 ,背腹型 ;叶柄具 5束维管束 ,进入小叶时分为 7～ 9束。茎和叶的初生维管束为双韧维管束。组织化学实验表明 ,绞股蓝人参皂甙主要分布在营养器官的同化组织及韧皮部薄壁细胞中 ,厚角组织。

Gynostemma pentaphyllum is a perennial vine.Its root system is composed of adventitious roots.The primary xylem of root is 2~4 arches,and the secondary structure of root is characterized by a thicker phelloderm.Young climbing stem has 5 angles ,and in its cross sections,there are 2 rings of vascular bundles,with 5 vascular bundles occurring in the outer ring and 4~5 ones in the inner ring,and the perivascular fiber is continuous.In contrast to young climbing stem,the base part of stem is round ,and in its cross section,the secondary xylem and secondary phloem have developed,the perivascular fiber becomes discontinuous,and the vascular bundles become a irregular ring.The leaf of this species is of palmately compound leaf,alternative,whit 5~7 leaflet ,dorsiventral.5 vascular bundles exist in petiole and branch into 7~9 after extending into leaflets.Both the primary vascular bundles of leaf and that of stem are bicollateral.The distribution pattern of ginsnosides in the vegetative organs of Gynostemma pentaphyllum were demonstrated by histochemical localization.Ginsnosides distributed mainly in the assimilating tissue and phloem parenchyma cells and much less were detected in epidermis,phelloderm and collenchyma.