糜子的大小孢子发生和雌配子体发育

1、大小孢子母细胞的减数分裂均为正常型:小孢子四分体有左右对称形、直列式和T形;大孢子四分体为直线排列。2、大孢子母细胞和四分大孢子的壁都有胼胝质沉积,胼胝质从大孢子母细胞的珠孔端壁开始积累,而后包围母细胞;消失的顺序是由合点端壁开始,再到侧壁,孢子之间的横壁最后消失。3、大小孢子母细胞减数分裂同时开始,同步进入粗绒期之后,雌性比雄性发育缓慢,以致二种母细胞的减数分裂不同时结束;在可育花中雌雄配子体是同时成熟的。4、成熟胚囊中反足细胞不立即进行细胞增殖,仍为三细胞;卵细胞无明显极性;助细胞极性明显。5、抽穗后花序基部不能完成减数分裂(未分化出花药唇片)的小穗是不生育小穗。

The Micro- and Mega-sporogenesis and the Development of Female Gametophyte in Panicum miliaceum L.

The meioses of megasporocyte and microsporocyte arenormal. The accumula- tion of callose commences with the micropylar end of megasporocyte and extends to the whole wall afterwards. The callose in the wall of linear megaspore tetrad disappears from chalazal end wall to lateral wall and lastly to the cross wall. The micro- and mega-sporocyte initiate meioses simultaneously, they complete meioses at different time, but the male and female gametophytes maturate at the same time in fertile flowers. After earing the infertile spiketets are those on the basal bart of inflorescence which cannot finish meiosis.