黄连体内黄连素的组织器官定位和根尖屏障结构特征研究

Location of berberine and development of apoplastic barriers on Coptis chinensis anatomcal structure

关键词:  黄连, 黄连素, 解剖结构, 组织化学

Key words:  Coptis chinensis, berberine, anatomical structure, histochemistry

摘要:

黄连(Coptis chinensis)是毛茛科著名药材,该文研究了黄连体内黄连素在组织器官中的分布规律和根尖屏障结构特征。在白光和荧光显微镜下,组织器官中黄连素在蓝色激发光下自发黄色荧光,黄连素-苯胺兰对染研究细胞壁凯氏带和木质化,苏丹7B染色栓质层,间苯三酚-盐酸染色木质化。结果表明:黄连不定根初生结构为维管柱、内皮层、皮层、外皮层和表皮组成; 次生结构以次生木质部为主、次生韧皮部和木栓层组成。黄连根茎初生结构由角质层,皮层和维管柱组成; 次生结构由木栓层、皮层和维管柱组成,以皮层和维管柱为主。叶柄结构为髓、含维管束的厚壁组织层、皮层和角质层。黄连不定根的屏障结构初生结构时期由栓质化和木质化的内皮层、外皮层; 次生结构时期为木栓层组成; 根状茎的为角质层和木栓层。黄连素主要沉积分布在不定根和茎的木质部,叶柄的厚壁组织层,木质部和厚壁组织是鉴别黄连品质的重要部位。黄连根尖外皮层及早发育,同时初生木质部有黄连素沉积结合,可能造成水和矿质吸收和运输的阻碍,也是黄连适应阴生环境的重要原因。

Abstract:

Goldthread(Coptis chinensis)is a famous medicinal plant in Ranunculaceae. We studied berberine locate in tissue and organ features, and apoplastic barriers developed in adventitious roots and rhizomes, and anatomic structures of adventitious roots, rhizmoes and petioles in different development stages. All samples were collected from Lichuan farmland, Hubei Province. We carried out the cell wall histochemistry under light and epifluorescence microscope, and the berberine in organ and tissue fluoresced yellow under blue exciting light that was refered as berberine hemisulfate-aniline stain for lignin which combine with lignin and fluoresce stronger yellow, berberine hemisulfate-aniline stain for Casparian bands fluoresced vivid yellow, and lignin fluoresced stronger yellow. Sudan red 7B stain for suberin showed reddish. Phloroglucinol-HCl stain for lignin showed cherry reddish. Primary structure of goldthread adventitious roots compose of vascular cylinder, endodermis, cortex, exodermis and epidermis; secondary structure compose of secondary xylem, secondary phloem and phellem. Primary structure of rhizomes compose of cuticle, cortex and vascular cylinder; secondary structure compose of phellem, cortex and vascular cylinder. Petioles compose of pith, sclerenchyma rings with vascular bundles, cortex and cuticle. The apoplastic barriers in adventitious roots compose of endodermis and exodermis; and endodermis, exodermis and phellem present in same development stages; and phellem in secondary structure. The apoplastic barriers in rhizmoes compose of cuticle in young stage, and phellem in age stage. Berberine deposite on primary xylem and secondary xylem of adventitious roots and rhizmoes, and on sclerenchyma rings of petioles. Xylem and sclerenchyma rings are important for medicinal quality of goldthread. Exodermis develop early and berberine anchor in primary xylem to root tips, which may prevent water and mineral to absorbing and transporting in goldthread adventitious root. The endodermis and exodermis and phellem of apoplastic barriers totally restrict water and mineral that transport in adventitious roots, among which only very few surface of root tips can absorb water and mineral; and berberine deposit and block up the xylem that result in slowing down of water and mineral transport, which explains why goldthread growth is very slow and need 5-6 years to harvest. These structure characteristics maybe the reasons for goldthread adapting to shade environment.