Research On The Reproductive Biology Of Tupistra Chinensis Baker

Tupistra chinensis Baker is a perennial herb; it belongs to Tupidtra Ker-Gawl in liliaceae. The Tupidtra Ker-Gawl mially distributed in Asia, contains about 20 species; China own almost 70 percent. T. chinensis Baker growing in 1000-2000 meters above sea level, such as shade and wet place of forest, stream or roadside. The study on Tupidtra Ker-Gawl mainly focus on tissues of root, stem and leaf, pollen morphology, cell karyotype, pharmacognosy, chemical constituents, pharmacological and other aspects, but the reports about reproductive biology of T. chinensis Baker are still rare. This paper discuss on the reproductive biology of T. chinensis Baker, the results could provide scientific basis for the cultivation and application of this plate.The main contents of this study: pollination biology, breeding system, pollen viability, stigma receptivity and so on. Using morphological observation, conventional paraffin sectioning and histochemistry staining to particularly explore the germination of the spores, development of male and female gametes, double fertilization, growth of embryo, endosperm and seed; Observing the material accumulation dynamics of anther and pollen wall when the development of corpus callosum by fluorescence microscopy; the mature pollen observed by scanning electron microscope; through observation and measurement to understand basic characteristics of the asexual reproduction. The results of this study indicate:1. Biological characteristics of floweringFlower bud of T. chinensis Baker become divided from late August to the second year of the end of march, it will florescence in April. T. chinensis Baker is in a spikes, each spikes have 20-30 flowers, flowering time will last 15-20 days. Single flower blooming time continue 4-5 days. The flower has 6 pieces of green or yellow green tepals, 6 ovate antherals, light yellow pollen and it will attached on the pollen sac, subglobose ovary, three lobed stigma, at the meantime.Breeding system of T. chinensis Baker is outcrossing and need pollinators. Hybrid index(OCI) is 4, the average value of pollen ovule ratio(P/O) is 59740, T. chinensis Baker can be carried out seeds and setting percentage is higher in nature; the male and female gametophyte is normal, but it could not get seed while it was transplanted to campus, so we conclude that Breeding system of T. chinensis Baker is outcrossing. The pollen contain high energy during the flowering, the receptivity of stigma is strong within one week of flowering, it will weaken, even to atrophy after a week.2. The characteristics of anther developmentThe anther has 4 rooms, fully differentiated of anther consist of epidermis, endothecium, middle(2-3layers) and tapetum layer; middle and tapetum layer ara degraded in the mature pollen stage, at the same time, inside of anther rooms was formed thichening bands fiber layer. The development of the anther wall is basic type, the tapetum is glandular tapetum.3. The formation of male and female gametesMeiosis of the male gamete is the successive type, forming dyad and tetrad spores, the kind of tetrad spores is symmetrical arrangement. The mature pollen is two cell type; the mature pollen is oval, with one germination ditch and distinct reticulate sculpture.The result of periodate-shiff reagent(PAS) staining indicate polysaccharides rarely accumulate in the anther tissue during the stage of the male gamete. As the anther developing, the polysaccharides increased. Single cell pollen began to accumulate polysaccharides, at last, the mature pollen have abundant polysaccharides.4. Spores occurrence and female gamete formationT. chinensis Baker has 3 locules, 6 pieces of ovules, 2 pieces of ovules per locules, the ovules is anatropous, bitegmic and tenuinucellus. The original female spore cells come from nucellar cell in the ovule primordial below the top layer; spore original cells directly develop into megaspore mother cell and divided into dyad cells by meiosis, the one in the micropylar end will degradate, other in the chalazal end continue to form two subcells by meiosis, at last develop two nuclear embryo sac. It will form four nuclear embryo sac and eight nuclear embryo sac through two mitotic, eventually become the mature embryo sac, it has one ootid and two synergid cells form egg apparatus at the micropylar end, the upper and lower polar cell fused into central cell, 3 antipodal cells degenerated earlier in the chalazal end. Embryo sac type of T. chinensis Baker is double spore.5. Development of embryo and endospermT. chinensis Baker fertilizes in the micropylar end. Two sperm into embryo separately fused with oocyte and central cell, zygote form basal cell and apical cell, apical cell divided to from globular embryo. Two sides cell division of globular embryo is not balance, the one side divide quickly and gradually form a large piece of cotyledon, and tend to surround the top of immature embryo and the other side; the other rarely divide, will not form the second cotyledon. As the growth of cotyledon, cotyledon gradually surrounds the top of immature embryo and forms clavate embryo. The embryo development type of T.chinensis Baker same as the monocotyledonous plant. The result of PAS indicate in the globular embryo suspensor have abundant starch grains. The development type of endosperm is helobial. After fertilizated the primary endosperm divided into two cells, they move to form the micropylar chamber and the chalazal chamber. Endosperm cells in the micropylar chamber form free nuclei of endosperm by mitosis, followed form endosperm cell. Endosperm cells in the chalazal chamber undergo a few times of nuclear division, it will not form endosperm cell until the seed mature.6. Seed germinationThe seed in the mature fruits of T. chinensis Baker mostly is 1-3. Seed consist of the seed coat, embryo and endosperm. Seed has ripening phenomena, the germination of seeds is difficult in nature, the rate is very low. Drying condition in door, the seed will lost viability and not germinate;The germination rate of seeds perseved in the wet sand is higher, up to 83.5%, seedling rate is 95% when the seed was germinated. During seed germination, radicle will first protrusion from the seed coat, embryo later unearthed and growed a piece of leave, the endosperm and cotyledon remain in the soil.7. Basic characteristics of asexual reproductionT. chinensis Baker reproduce by asexual in the natural condition, the rhizome can give birth to the growth of transverse creeping rhizome, top of the creeping rhizome can reach soil surface to form new plants. In addition, the stems near ground can produce vegetative, thereby developing a new ground base on the branch, branch roots will go deep into the soil. According to the origin of organ clonal, T. chinensis Baker is a rhizomatous clonal plants; According to the different branched of organ clonal, it belongs to the axis of the clonal plant; According to the discrete division of the same clonal ramets, it belongs to the phalanx clonal plants; According to the amphitropous structure of the connected ramets, it belongs to the long life and spacer clonal plants.