油松无性系雌雄配子体的形成及胚胎发育

油松雄球花于６月下旬开始分化，小孢子发生在翌年的４月２０日左右，４月底或５月初散粉．成熟的花粉粒为４个细胞．雌球花７月中旬分化，次年４月下旬或５月上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等阶段后，５月下旬受精，从传粉到受精约需１３个月．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３个半月．不同无性系在雌雄球花发端时间和大小孢子发育进程上存在较大差异，观察的５个无性系进入同一发育阶段的时间最多可相差１０ｄ，平均变幅为一周上下．该文还对新梢生长与花芽分化、胚珠和花粉败育作了讨论．

Formation of Male and Female Gametophytes and Development of Embryo in Pinus tabulaeformis Carr.

The male strobilus differentiates in late June,while the female strobilus in middle July.The microsporogensis occurs on about April 20 of next year.The mature pollen,which is pollinated in late April and early May,is composed of 4 cells.The megasporophyte is formed in late April and early May of next year,and undertakes meiosis to form megaspore.A female gametophyte develops from free nuclei,cell and archegonia phase to a mature egg cell.Fertilization takes place in late May.The interval between pollination and fertilization is about 13 months.Embryogeny includes proembryo,young embryo and mature embryo and needs three months.There are great differences in differentiation time and development process of male and female strobilus for 5 observed clones.In addition,the relations between shoot growth and strobilus differentiation,abortion of embryo and pollen are also discussed.