西瓜小孢子囊发育及雄配子体发生的观察

OBSERVATIONS ON THE DEVELOPMENT OF MICROSPORANGIUM AND THE EMERGENCE OF MALE GAMETOPHYTE IN WATERMELON (CITRULLUS LANATUS)

西瓜(Citrullus lanatus)小孢子囊的孢原细胞出现在雄花原基出现后4—6天,孢原细胞数目推测只有一列;初生造孢细胞经过2—3次分裂,形成次生造孢细胞。开花前7—8天,小孢子囊发育健全,小孢子母细胞进入减数分裂期。同一花药不同花粉囊相同一药室,花粉母细胞减数分裂和小孢子的发育,并不是高度同步的。绒毡层为异型细胞,腺质绒毡层。雄配子体的发育开始于开花前6—7天,充分成熟的西瓜花粉已分裂为三细胞花粉。

The archesporial cell of microsporangium in watermelon appeared in 4-6 days after the male flower primordia came out, it is supposed that the number of archesporial to be only one row. Primary sporogenous cells divided for 2-3 times and formed secondary sporogenous ceils. In 7-8 days before flowering, the microsporangiam developed well and themicrospore mother cells entered into the period of meiosis. It is not synchronous highly that the meiosis of pollen mother cells and the development of microspore in the same anther but different pollen sac and in the same anther chamber. The tapetum ceils are the heterotypiccells and the glandular tapetum. The development of male gametophyte started in 6-7 days before flowering. The full-matured pollen in watermelon have already divided into three cells.