Studies On Embryology Of Bupleurum Scorzonerifolium And Dynamic Changes On Storage Product During Fruit Development In Bupleurum Chinense

Bupleurum scorzonerifolium Willd. and Bupleurum chinense DC. confirmed for a long history as medical uses, belong to Bupleurum L. in Umbelliferae. Bupleurum Radix is a popular medicine in China characterized as febrifuge, analgesic, anti-inflammatory drugs and so on. Because of increasing need for market, serious deficiency of wild resource and low seedlings of Bupleurum scorzonerifolium and Bupleurum chinense sprout in its universal planting. Recently, lots of studies were carried out on chemical component and pharmacology of Bupleurum Radix, embryology of Bupleurum chinense, but embryology research on Bupleurum scorzonerifolium is lack. In addition, it was reported that the seeds are characterized by post-maturation phenomenon from morphological point, indicating that certain endogenous inhibitory substances are produced within the seeds of Bupleurum scorzonerifolium and Bupleurum chinense. As a result, embryology studies on Bupleurum scorzonerifolium were determined using wax-sliding and semi-thin technique; UV spectrophotometry and GC-MS were used for measuring the dynamic changes of coumarin, soluble sugar and protein, starch, fatty acids during different developmental stages of fruit, with the aim to provide theoretical evidence for broad planting of Bupleurum scorzonerifolium and Bupleurum chinense.1. Microsporogenesis, formation of male gametophytes in Bupleurum scorzonerifoliumAt the initial stage, antherogenous ontogenesis of Bupleurum scorzonerifolium is characterized by a group of subepidermal meristem cells at the corner of anther, namely archesporial cells. The archesporial cells undergo a periclinal division to form the primary sporogenous cells and primary parietal cells. The primary parietal cells develop into layers of anther wall cells. The primary sporogenous cells divide into secondary sporogenous cells, and develop to microspore mother cells ultimately. The microspore mother cells divide through a mitosis process to give birth to tetrahedral tetrad, then microspores are finally formed by a combination course of tetrahedral tetrad separation and lysis of callose walls. Ultimately, a 3-cell type of mature pollen is formed by mitosis of microspores.2. Megasporogenesis, formation of female gametophytes in Bupleurum scorzonerifoliumThe ovary is distinguished by two locules and one ovule in each locule of Bupleurum scorzonerifolium. The megaspore immediately occurs from an expanded archesporial cell under nucellus epidermis, the megaspore mother cell sequently develops into dyad and tetrad, the megaspore located at the pole of chalaza forms to the functional megaspore, the functional megaspore sequently develops into single nuclear embryo sac, double-nuclei sac and 8-nuclei embryo sac stages. Eventually, a mature embryo sac characterized by 7-cells with 8-nuclei is formed.3. Embryo and endosperm formation in Bupleurum scorzonerifoliumThe zygote undergoes a mitosis process to form an apical cell and a basal cell. Later, the basal cell divides transversely and lognitudinally to form suspensor cells and the apical cell continuously divides to form four-celled proembyo,16-celled proembryo, clubbed shape proembyo and globular embryo sequently which differentiate into heart-shape embryo and fish torpedo embryo.The primary endosperm nucleus occurs after polar nucleus fertilization, which is earlier than zygote. The endosperm nuclei undergo continuous mitosis, producing aboundant dissociative endosperm nuclei locating around the embryo sac. Next, the dissociative endosperm nuclei produce cell walls to develop mature endosperm.4. Development of embryo of Bupleurum scorzonerifolium during collection periodThe seeds of Bupleurum scorzonerifolium were characterized by serious post-maturation phenomenon from morphological point of role. Statistics studies on embryo show that the embryo rate of globular embryo, early heart-shape embryo, late heart-shape embryo is at 26%,29.6% and 37.4% sequently, however merely 7% is determined for fish torpedo embryo. And rarely dicotyledonous embryo is detected in the experimental fruits.5. Changes on fatty acids,soluble sugar,starch and the soluble protein during different developmental stages of Bupleurum chinense fruit The fruits mainly contained four kinds of fatty acids, including palmitic acid, stearic acid, oleic acid and linoleic acid. Palmitic acid and stearic acid are showing a highest level during the earliest stage, and revealing a decreased trend later; however the content of oleic acid and linoleic acid both increases during the entire developmental stages and a negative relevancy are also revealed between oleic acid and linoleic acid; the total content of shows increased trend during the developmental stages, and reach to the highest level when fruits mature.The soluble sugar is decreased during the maturation of fruit; the starch and the soluble protein are increasing during the early developmental stages, while reduced at mature stage. As a result, it could be concluded that most of soluble sugar and protein, starch should be transferred into fatty when the fruit matured.6. Endogenous inhibitory substance in Bupleurum chinense fruitCertain mount of coumarin is detected in Bupleurum chinense, indicating a relative high content during the early ovary expanding stage, gradual decreased phenomenon at later stages, and a lowest content at globular embryo stage. However, the content of coumarin increases evidently later, and reaches to the highest level at fish torpedo embryo stage.The results reveal that, saikosaponin and water distilled solution can inhibit the seed germination obviously. No evident inhibition is shown on cabbage seed germination with low concentration of coumarin, but a prominent inhibition to young roots is found. An obvious inhibition is gained by high concentration of coumarin to both young roots and seeds of cabbage. Besides, the cabbage seeds treated by three different groups including coumarin, saikosaponin and water distilled solution, are characterized by most obvious inhibition with coumarin, secondly with saikosaponin, and weakest inhibition with water distilled solution.