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应用石蜡制片技术研究了大车前胚乳与胚发育过程的细胞胚胎学特征,为车前科胚胎学及分类地位的确立提供相关资料。结果表明:大车前成熟雌配子体为七细胞七核的蓼型。经双受精后形成合子与初生胚乳核。胚乳发育类型为细胞型,初生胚乳核第1次横分裂产生珠孔室与合点室胚乳细胞。珠孔室胚乳细胞经1次纵分裂或2次连续相交的纵分裂形成2个或4个胚乳细胞;进而同步进行横分裂形成2排,即4个或8个胚乳细胞;靠近珠孔的2个或4个胚乳细胞分化并发育成为单核的管状胚乳珠孔吸器;靠近合点室胚乳细胞的2个或4个细胞进行各个方向的分裂形成胚乳本体,并将合子分裂所形成的胚包围其中;与此同时,合点室胚乳细胞的细胞核进行1次核分裂但不伴随胞质分裂,在合子期便形成具有两个细胞核的胚乳合点吸器;胚乳吸器为胚乳本体的发育从珠被与合点吸收并转送营养物质。胚胎发生属于柳叶菜型,经原胚期、心胚期、鱼雷胚、子叶胚形成成熟种子。珠被绒毡层发达。对胚乳本体以及球胚的流式细胞仪细胞核DNA分析表明,胚的DNA含量为二倍体,而胚乳为三倍体。
The paraffin-embedded technique was used to study the characteristics of embryo embryo and embryo before embryo. The data of embryo embryology and taxonomic status were provided. The results showed that the mature female gametophyte was a seven-cell seven-nucleus Polygonum type. After double fertilization, zygotes and primary endosperm nuclei are formed. The type of endosperm development is cell type, and the primary transverse endosperm nucleus translocates to produce the peritoneal cavity and the endosperm cells. Two or four endosperm cells were formed by longitudinal division or two successive divisions of longitudinal division of endosperm cells in the peritoneal cavity; further transverse division was performed to form two rows, ie, four or eight endosperm cells; 2 Or four endosperm cells differentiate and develop into a single-core tubular endosperm bead-shaped aspiration; near the endosperm cells in the synaptic chamber of two or four cells in all directions of the division of the formation of endosperm body, and zygotic division of the embryo surrounded by the formation of which At the same time, the nucleus of the endosperm cells in the conjunctival chamber undergoes a nuclear division without accompanying cytokinesis, and the endosperm junctional outlet with two nuclei is formed at the zygotic stage. The endosperm aspiration is the development of the endosperm itself absorbed from the integuments Transfer nutrients. Embryo belongs to the willow-type, the original embryo stage, the embryonic stage, torpedo embryos, cotyledons embryo formation of mature seeds. Bead tapetal developed. Flow cytometric nuclear DNA analysis of endosperm as well as bulb showed that embryos had a diploid DNA content and an endosperm triploid.