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作 者 ：彭　杰;申家恒

期 刊 ：园艺学报 2005年 32卷 5期 页码：812-817

关键词：大白菜；受精；

Keywords:Brassica campestris ssp. pekinensis, Fertilization,

摘 要 ：对3个大白菜(Brassica campestris ssp. pekinensis) 品种的受精过程及其各阶段持续的时间进行了研究。其结果如下: 1. 授粉后2～3 h, 花粉在柱头上萌发。2. 授粉后4～8 h, 花粉管在花柱中生长。3.授粉后8～14 h, 花粉管在子房中生长并通过珠孔进入胚珠。4. 授粉后16 h, 花粉管进入胚囊, 破坏1个助细胞, 并将内含物释放入该助细胞内。5. 授粉后16～18 h, 精核向卵细胞移动并进入卵细胞。授粉后18 h,精核附在卵核的核膜上。6. 授粉后20 h, 精核进入卵细胞核, 精核染色质逐渐松解; 授粉后24 h, 出现雄性核仁。受精卵核内有一明显大的雌性核仁和1个较小的雄性核仁, 此时形成合子。精核染色质在卵核内分散延续的时间长达4 h左右。7. 授粉后32～34 h, 合子进行第1次分裂。大白菜合子静止期8～10 h左右。8.受精前二极核合并成次生核或不合并, 位于卵细胞的合点端。9. 授粉后16～18 h精核向极核或次生核移动。授粉后18 h, 精核附在极核或次生核的核膜上。10. 授粉后20 h, 精核进入1个极核或次生核, 二者进行融合。精核与极核或次生核的融合过程同精核与卵核的融合过程相同, 只是精核与极核或次生核融合速度较快。精核染色质在极核或次生核里分散的时间大约为2 h。11. 授粉后22 h, 形成初生胚乳核, 在分裂前常常看到初生胚乳核内的雌雄性核仁仍未合并。12. 授粉后24 h, 初生胚乳核进行第1次有丝分裂。

Abstract:This paper reported the p rocess of fertilization in Brassica campestris ssp. pekinensis and its duration of each stage. The results are as follow: 1. Pollen germinates on stigma 2 - 3 h after pollination. 2. 4 - 8 hours after pollination, pollen tube grows in style. 3. 8 - 14 hours after pollination, pollen tube grows in ovary and gets into ovule via micropyle. 4. 16 hours after pollination, one sperm nucleusmoves to egg and enters it. 5. The sperm nucleus adheres to the nuclearmembrane of egg 18 hours after pollination. 6. 20 hours after pollination, sperm nucleus enters egg nucleus and male chromatin gradually disperses and 24 hours after pollination, male nucleolus appears. A large female nucleolus and a smallmale nucleolus occur in the nucleus of fertilized egg, and zygote formed. The dispersing of sperm chromatin in egg nucleus takes about 4 hours; 7. 32 - 34 hours after pollination, the division of zygote begins. The dormancy stage of the zygote lasts for about 8 - 10 hours; 8. The pair polar nuclei lie in chalazal end to egg before fertilization, which fuse into a secondary nucleus or not; 9. 16 - 18 hours after pollination, the sperm nucleus moves to the polar nuclei or the secondary nucleus. 18 hours after pollination, sperm nucleus adheres to the nuclearmembrane of polar nuclei or that of the secondary nucleus; 10. 20 hours after pollination, sperm nucleus enters one of the polar nuclei or the secondary nucleus and the triple fusion takes place. The process of fusion is similar to the karyogamy, and faster than that. The dispersing of the sperm chromatin in polar nucleus or secondary nucleus takes about 2 hours; 11. 22 hours after pollination, the primary endosperm nucleus formed. The female and male nucleoli can not fuse with each other before mitotic division of the p rimary endosperm nucleus; 12. 24 hours after pollination, the division of the p rimary endosperm nucleus takes place.

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