Developmental Anatomy Of Vegetative Organs And The Cytochemical Localization Of Saikosaponin In Bupleurum Scorzonerifolium Willd

Bupleurum scorzonerifolium Willd. is a perennial herbaceous plants in Bupleurum L, Umbelliferae. It has been one of the traditional chinese medicinal materials and has a long medicinal history. Because of its significant medicinal value, the concern of their research became comprehensive and penetrated into all aspects, mainly in biology, chemical composition, cultivation breeding, pharmacology and clinical applications and so on. But the exact localization of its main medicinal ingredients saikosaponin had not been reported. Therefore, in this paper we use technology of plant anatomy, histochemistry and cytochemistry to investigate the structure and development of vegetative organs and the histochemical and cytochemical localization of its active ingredients saikosaponin. The results are as follows:1. The developing process of root, stem and leaves in B. scorzonerifolium are consistent with the general development laws of dicotyledonous plants. The primary xylem is diarch, triarch is few. Mature structure mainly depends on the secondary structure. The perennial root had the similar structure with the annual one, but there have some differences in the quantity of cells and structure of each part. Secretory canals of annual root were only distributed in the pericyclic parenchymna. But they are distributed both in the pericyclic parenchymna and the secondary phloem in perennial roots. The development of leaf includes original meristem, primary meristem and mature structure of three stages. Its leaves are typical isobilateral leaves. Secretory canals in stem are mainly distributed in the cortex and pith, in the leaves it are mainly distributed in the vascular bundles, they were all primary ones.2. Histochemistry of roots, stems and leaves in B. scorzonerifolium were studied. The results showed that during the different developmental stages of root stems and leaves, the distribution and content of saikosaponin are different. In early development of the root, saikosaponin are mainly distributed in the cortex. In the secondary structure, they are mainly distributed in the pericycle and the cambium. In the mature stem, saikosaponin are mainly distributed in the cortex. In the mature leaves, low content of saikosaponin are distributed throughout the mesophyll tissues.3. Lead acetate precipitation method was used for ultracytochemical localization of saikosaponin in B. scorzonerifolium root. The relationship between structural development and saikosaponin accumulation in the root was discussed by transmission electron microscope. The primary and secondary structure of root of B. scorzonerifolium resembled those of usual dicotyledon. In the primary meristem, saikosaponin was distributed in the dermatogen and periblem. In the primary structure, saikosaponin was distributed in parenchyma cells of the epidermis, cortex, pericycle, primary phloem and protoxylem, among which pericycle and primary phloem were the main storage site. In the secondary structure, saikosaponin was mainly distributed in parenchyma cells of the pericycle and secondary phloem. Cells of the secondary xylem and vascular cambium also contained a small amount of saikosaponin. Dictyosomes might be related to the synthesis of saikosaponin, plasmodesmata participated in the transport of saikosaponin.4. SSd was localized by immunoelectron microscopy during the development of root, stem and leaf in B. scorzonerifolium. The result showed that the distribution pattern of the gold particles, which could be detected as SSd, changed as cells matured. SSd's quantity had a distinct different among root, stem and leaf. It was evidently more in roots than that in stem and leaf. The stem was the lowest. Antibody with gold particles (under transmission electron microscopy) for localization was mainly displayed in the vacuole of cells in each part and a few in the protoplasm. The organelle nearly has no SSd been observed. This result indicated that the vacuole is the main storage site of SSd. The particle of SSd was few in the control. The method that we used provides an evidence for further research of SSd localization in B. scorzonerifolium and it showed that this is a credibility method.