Abstract: The contractiaction of the protoplasts during the early development of the microsporangium os observed and the callose wall is fprmed at the same time.The microspor mother cells are separated from each other and were surrounded by callose wall before meiosis.The small pore about 0.2 to 0.3micron in diameter wihin the callose wall was observed.After the tetrad was formed,the nuclear evelope and the golgi bodies show a particular activity which is provably related to the exine depositing.

Key words: Pinus yunnansis

摘要： 云南松（Pinus yunnanensis Fr．) 小孢子囊发育早期，原生质体发生收缩、同时形成胼胝质壁。小孢子母细胞减数分裂前互相分离，并被胼胝质壁包围。在壁上有约0．2微米的小孔。四分体小孢子形成后，核被膜及高尔基体显得非常地活跃，他们可能与外壁的沉积有关。这个现象在早期四分体阶段出现。内壁的形成是在自由小孢子时期，开始高尔基体和核被膜仍较活跃，但随之下降。内质网和线粒体增多，许多来自内质网的泡囊通过质膜被排放到内壁中去。乌氏体与花粉外壁之间观察到了孢粉素带.

关键词: 云南松, 超微结构, 小孢子发生