华北落叶松雌雄配子体的形成及胚胎发育

华北落叶松的雄球花７月中旬开始分化，小孢子发生在次年的３月下旬至４月上旬，４月底散粉，成熟花粉为五个细胞。雌球花７月初分化，翌年４月上、中旬形成大孢子母细胞，经减数分裂后，形成大孢子。雌配子体经历游离核、细胞化、颈卵器及卵细胞形成几个阶段后，６月上、中旬受精，从传粉到受精约需４０ｄ．胚胎发育包括原胚、胚胎选择及发育和胚胎成熟３个阶段，历时两个半月。

Development of Male and Female Gametophytes and ofEmbryo in Larix principis-rupprechtii Mayr.

The male flower differentiates in middle July, while the female flower in earlyJuly. The microsporogenesis occurs in late March and early April of the next year. The ma-ture pollen, which is pollinated in late April, is composed of 5 cells. The megasporocyte isformed in early and middle April of the next year and undertakes meiosis to form megasporein early May. A female gametophyte develops from free nuclei, cell and archegonia phase to amature egg cell. Fertilization takes place in early and middle June. The interval between polli-nation and fertilization is about 40 days. Embryogeny includes proembryo, young embryo andmature embryo and needs two and a half months.