Studies On The Flower Bud Differentiation, Pollination And Fertilization Of Stylosanthes Guianensis Cv. Reyan No.2

Stylosanthes guianensis cv. Reyan No.2 is a herbacepus plant of Leguminosae. The study on the flower bud differentiation, the procedure of self-pollination, fertilization, embryonic development, endosperm development and the relationship between embryo and endosperm of Stylosanthes guianensis cv. Reyan No.2 was conducted by the means of paraffin sectioning, fluorescence staining and squash. The main research results are as follows:(1):In the stage of vegetative growth, the root of terminal bud heaved to be a sharp angle while the root of the peak of stem apex to which the flower bud differentiation happened heaved to be an obtuse angle with the meristem surface. The hemisphere cone of meristem become grow prominently,then,extend a circular cone.the wintering bud prime was accompolish;Bristle of the stem apex became cruder, stiffer and thicker when the Flower Bud differentiated, and the pubescence of terminal bud basal looked comparatively soft.(2):The research on the self-pollination of Stylosanthes guianensis cv. Reyan No. 2 under different temperature condition illustrated that the temperature, to some extent, influences the blooming and budding time of the floret of Stylosanthes guianensis. That is to say, when the temperature was higher, the alabastrums grew in advance. The floret changed enormously during the period of fertilization, and porocalyx and corolla grew rapidly in the stage of self-pollination. When the length of porocalyx approached to that of corolla, self-pollination was done.(3):Observe the posy form change in the process of pollination and fertilization of Stylosanthes guianensis cv. Reyan No.2 and the procedure of double fertilization. At 6 o'clock of morning, most of the alabastrums had self-pollinated, and the pollen grains on the necking began to bud after 2-3 hours.2-3 hours later after pollinating, pollen tubes grew along edges of ovary intine and then entered into ovule for rorogamy.5-6 hours after blooming, egg cell fusion, and, almost at the same, sperm and polar nucleus fused.(4):After 21-22 hours of anthesis, the zygote started its first division to form a two-celled proembryo and experienced a series of developing stages such as single-row cell embryos, bat-like embryos, globular embryos, heart embryos, torpedo embryos, juvenile embryos and spreading-growth stages. The embryo grew maturely 25-28 days later after anthesis. The development of the embryo was the soland type. At the enlarging stage, the embryo began the accumulation of starch and protein sequentially. The primary endosperm nucleus began to carry on mitosis 8-10 hours later after anthesis. The development of endosperm was designated as nuclear type. The endosperm started to degenerate as the embryo grew up to fill almost the whole embryo sac and disintegrated completely but with a thin layer of remains left when the embryo matured.(5):The earliest observed fission of primary-endosperm began to conduct 8-10 hours later after the floret bloomed, and the fission of primary-endosperm could be always seen in the embryo sac before the fission of zygote conducted. The early endosperm free nuclei proliferated in the form of karyomitosis. In the time of diploidcells,3-6 free nuclei can be found in the embryo, and the size of free nuclei was very closely, and all had a one nucleolus.3-7 days later after blooming, free nuclei mixed with the ambient protoplasm to be a skim which surrounded the rataria and embryo sac, and then formed a layer of endosperm membrane.10 days later after blooming, there existed 2-4 layers of endosperm cells in the embryo sac perisporium, and at this moment, the free nuclei and endosperm cells coexisted. When the endosperm occupied the whole embryo sac, endosperm began to degenerate, the cells were separated from each other, cytoplasm disintegrated, and then hypochromatosis occurred, and at last, only one layer of endosperm remaining left which surrounded the mature embryo.(6):On the 25th day, seeds totally became to be black. There was, to some extent, some relevance between episperm and the colour of embryo, and the time of changing colour of episperm is 2-3 earlier than that of embryo. It took Stylosanthes guianensis cv. Reyan No.2 about 25-28 days from blooming to totally maturing.