长喙毛莨泽泻双受精过程的细胞学观察

CYTOLOGICAL OBSERVATION ON THE DOUBLE FERTILIZATION IN RANALISMA ROSTRATUM

对长喙毛莨泽泻双受精过程进行了细胞学观察，结果表明，开花前３ｈ已可观察到花粉管进入胚囊，开花前２ｈ至开花后８ｈ，大部分雌、雄性核发生融合．合子内的雌、雄性核仁可以融合，以一个大核仁的形式进入分裂期，但核仁正在融合或尚未开始融合的合子同样可以进入分裂期．初生胚乳核内的核仁存在３种情况，即３个核仁或者不融合，或者精子核仁与珠孔端极核核仁融合，或者３个核仁融合成一个大核仁．配子融合属于有丝分裂前的配子融合类型．同一朵花中不同心皮的受精过程有一定顺序，即自花托下部逐渐向上部完成受精作用．

Ranalisma rostratum is a cleistogamous plant. The pollen tube which had entered embryo sac was observed 3 hours before anathesis. During 2 hours before anathesis and 8 hours after anathesis,most of the female nuclei fuse with the male nuclei. Geneally,the fusion of the male and female nucleolus takes place before the division of the zygote. Sometimes, the zygote in which two nucleoli are fusing,even do not begin to fuse,also can enter the division stage. Nucleoli in the primary endosperm nucleus are of three states: 3 nucleoli do not fuse,or the sperm nucleolus fuses with the nucleolus of the polar nucleus presented in the micropylar end,or 3 nucleoli fuse and form a large nucleolus. The double fertilization belongs to the premitotic syngamy. Carpels on the receptacle of a flower are fertilized sequencely,i. e. from the lower carpels of the receptacle to the upper ones.