黄花菜胚囊受精前后的超微结构观察

 应用透射电镜技术研究黄花菜（Hemerocallis citrine Baroni）助细胞、卵细胞、中央细胞、合子与初生胚乳核的超微结构特征。结果如下：助细胞有高度发达的丝状器；一个助细胞在花粉管进入后退化；宿存助细胞在合子期退化。受精前，卵细胞、助细胞合点端无壁，细胞膜完整；受精后，合子被完整的细胞壁包围。受精前超微结构特征显示卵细胞代谢活动低，合子期的代谢活性被激活；中央细胞、初生胚乳核代谢活性较高。卵细胞质中的精核由双层核膜包被，染色质高度凝聚，核孔数少。助细胞、卵细胞、中央细胞缺乏中央大液泡是黄花菜成熟胚囊的显著特征。

Ultrastructrue of the Embryo Sac Before and After Fertilization in Day Lily(Hemerocallis citrina)

We used transmission electron microscopy to study the ultrastructural changes in embryosac before and after fertilization，including synergid，egg，central cell，zygote and primary endospermnucleus of Hemerocallis citrina，so as to provide information on the reproductive biology of angiospermsand related research into day lily. Results were as follows：Both of the two synergids had highly developedfiliform apparatus，and one degenerated after pollen tube penetrated in，the other persisted until zygophase.The chalazal end of egg and synergid cells lacked cell wall before fertilization. But after fertilization，zygote had integrated cell wall. Ultrastructural characteristics suggested that the egg which was inactivewith low metabolism could be activated by fertilization，and both the central cell and primary endospermshow high metabolism. Sperm nucleus with double membrane，highly condensated chromatin and a fewnuclear pores immersed in the cytoplasm of egg. The remarkable characteristic of mature embryo sac ofday lily was that there was no large central vacuole in synergids，egg and central cell.