Study On Reproductive Biology Of Tricyrtis Maculata (D. Don) Machride

Tricyrtis maculata (D. Don) Machride is a kind of perennial herbs of Liliaceae which hasan important position in the process of plant evolution. Currently, there are many researchliteratures discussing the plant sexual reproduction, most of them reports reproductive of theliliaceous plant. However, the research on plants of the T. maculata (D. Don) Machrideis isrelatively less, Mainly concentrating in the application of garden plant, the basis cytologicalanalysis, and introduction of the medicinal value of T. maculata (D. Don). Few studies on T.maculata (D. Don) Machride reproductive biology, especially on the embryology of T.maculata (D. Don) Machride still belongs to blank.In this study，The Megasporogenesis, microsporogenesis, development of female andmale gametophyte, some detailed research on the processes of double fertilization,embryogenesis, endosperm and seed development of T. maculata (D. Don) Machride wereobserved by the method of paraffin sections. Discusses the characteristic of its embryonicdevelopment as well as the factors that influence the T. maculata (D. Don) Machrideembryonic development for the systematic study of basic research point of T. maculata (D.Don) Machride.In addition, the use of fluorescence microscopy to observe the corpuscallosum and pollen anther wall accumulated during the development of dynamic material;using scanning electron microscopy to observe the morphology of mature pollen. The resultsof the study enriched the content of liliaceous plant research, as well as liliaceous plantsystem research to provide the basis of reproductive biology.The main results as follows:(1) The anther is four sporangiate and the development of antherwall is the monocotyledonous type, the anther wall is composed of epidermis, endothecium,middle layer and tapetum. The epidermise consisit of one layer of cells and still existed as theanther matured. The endothecium developed banding-shaped thickenings when the anthermatured. The young anther wall has2layer middle layers and degenerated when maturity ofthe anther. The tapetum belong to secretory type and degenerated at the time of anthermatured.(2) The cytokinesis of the microspore mother cells in meiosis is of successive type.The microspore tetrads are tetrahedral and isobilateral spore. The mature pollen grain is of the2-celled type,with a single germination ditch.(3) The ovary has three chamber which hasmany ovule that is double integuments, tenuinucellate and anatropous. The archesporiumdirectly functions as the megaspore mother cell. After meiosis, the megasporocyte divides into linear or T-shaped type tetrads. The megaspore in chalaza end usually is functional one. Theembryo sac is of a polygonum type.(4) The fertilization is of micropyle type. Two spermsentered the embryo sac fertilized the egg and central cell and the syngamy belong topremitotic.(5) The development of endosperms of the Nuclear type. The division of theprimary endosperm nucleus and a few subsequent divisions are not accompanied by wallformation. Endosperm nuclei begin to become celled with the formation of the free cell wallat the globular peoembryo.(6) The zygote has a longer period of dormancy and slower rate ofdevelopment than the endosperm. The embryogeny corresponds to the Solanad type. Thezygote divides transversely and gives rise to a2-celled proembryo including a basal cell (CB)and a terminal cell (CA). Before long, both of the CB and CA in2-celled proembryo dividetransversely and give rise to a linear4-celled proembryo. The two basal cells of the4-celledproembryo undergo further divisions two times and give rise to a8celled suspensor. The twoterminal cells of the4-celled proembryo divide transversely and longitudinally many times toform the embryo body. When the seeds are mature, the embryos are not differentiated in toorgans yet. The embryo is the shield shaped when seeds are released from the capsule. Theseeds composed of the testa, embryo and endsperm.(7) There are some abnormal phenomenain the development of the anther that bring about the pollen degeneration. At different stagesof process of anther development, it appears anomalies development that lead to pollenabortion. In the course of ovule development, transversely and give rise to a linear4-celledproembryo. The two basal cells of the4-celled proembryo undergo further divisions two timesand give rise to a8celled suspensor. The two terminal cells of the4-celled proembryo dividetransversely and longitudinally many times to form the embryo body. When the seeds aremature, the embryos are not differentiated in to organs yet. The embryo is the shield shapedwhen seeds are released from the capsuleEach locule only1columns of ovules develop andform seed.(8) Mature seed of T. maculata (D.Don) Machride make up with the seed coat,embryo and endosperm. The shape of mature seed was flat, wide oval, testa leathery, brown,reticulate sculpture surface. Observation on seed section,, The seed coat have4layersstructure, respectively development by the inner, outer integument, the out cell wall of outertesta is obvious thickening. When seed of T. maculata (D.Don) Machride mature withoutorgan differentiation，after six months of Sand-hidden and found that the embryo is still noorgan differentiation, and therefore infer seed dormancy particularly long time.(9) In theprocess of microspore mother cell meiosis, staining by the water-soluble aniline blue,observing under the light blue fluorescence excitation with fluorescence microscope,Microspore mother cell walls do not observe blue fluorescence, in another words, there is not callose. But the whole outer wall and between cells emit blue fluorescencein in the dyadand tetrad, it means callose wall is produced. At the end of meiosis, after microsporeformation, callose wall gradually disintegrate.(10) Observed under electron microscope, themature pollen are ovoid, with a single germination ditch, pollen surface is relatively smoothand have irregular protrusions, but no obvious reticulate sculpture.(11) T. maculata (D.Don)Machride appear double female spore phenomenon, but in the late process of ovuledevelopment was not observed two embryo sac development phenomenon, it further explainthe emergence of double archesporial is an accidental phenomenon in the process of ovuledevelopment of T. maculata (D.Don) Machride.