【摘要】 观察了甜菜双受精的全过程,主要结果如下:授粉15小时后,花粉管破坏一个助细胞,释放出二个精子,精子为圆球形,具细胞质鞘;授粉17小时后,精子与卵细胞融合;授粉21小时后,形成合子;授粉25小时以后,合子进行第一次有丝分裂,合子的静止期约为4小时左右;授粉17小时以后,精子与次生核接触并融合,精核与次生核的融合比精卵融合要快;初生胚乳核的第一次分裂早于合子的分裂,发生在授粉20小时以后,初生胚乳核的静止期大约为2小时左右;甜菜的受精作用属于有丝分裂前配子融合类型;从合子到形成两个细胞原胚期,仍可见到多余的精子进入胚囊,但没有见到多精受精的现象。更多还原

【Abstract】 The whole process of double fertilization in sugar beet has been observed, the main results are as follows: About 2 hours after pollination, the pollen grains germinate, the sperms in the pollen tube are long-oval. 15 hours after pollination, the pollen tube destroys a synergid and releases two sperms on one side or at the chalazal end of the egg cell. The sperms are spherical each having a cytoplasmic sheath. 17 hours after pollination, one sperm enters the egg cell, and the sperm nucleus fuses with the egg nucleus rapidly. 21 hours after pollination, the zygote is formed. In the meantime, the primary endosperm nucleus has divided into two free endosperm nuclei. 25 hours after pollination, the zygote begins to divide, forming a two-celled proembryo. The dormancy stage of the zygote is about 4 hours. In the meantime the endosperm is at the stage of four free nuclei. 17 hours after pollination, the sperm nucleus comes into contact and fuses with the secondary nucleus. The sperm nucleus fuses with the secondary nucleus.faster than the sperm with the egg. The first division of the primary endosperm nucleus is earlier than that of the zygote, it takes place about 20 hours after pollination, the dormancy stage of the primary endosperm is about 2 hours. The endosperm is free nuclear. The fertilization of sugar beet belongs to premitotic type of syngamy. From the stage of zygote to the two-celled proembryo, it can be seen that additional sperms enter the embryo sac, but polyspermy has not been observed yet.更多还原