一年蓬的胚胎学研究

对一年蓬大小孢子、雌雄配子体、受精、胚乳和胚的发育过程进行了观察研究。结果显示:花药4室;药壁发育属于双子叶型,由表皮、药室内壁、1层中层和1层绒毡层组成;花药成熟时表皮退化,药室内壁宿存,其细胞柱状伸长,纤维状加厚;中层形成不久随即退化;绒毡层于小孢子母细胞减数第一次分裂前期开始原位退化,小孢子时期完全退化,属腺质绒毡层。小孢子母细胞减数分裂为同时型,小孢子四分体主要为四面体型,兼有十字型和左右对称型;成熟花粉粒为3-细胞粒。子房下位,两心皮一室,单胚珠,基生胎座,单珠被,薄珠心,倒生胚珠,具发达的珠被绒毡层;珠心表皮下分化出大孢子孢原,孢原细胞直接发育为大孢子母细胞;直线形四分体,合点端为功能大孢子,胚囊发育类型为蓼型,存在二倍体孢子生殖的胚囊;两极核在受精前融合为次生核,珠孔受精;胚乳发育属核型,具胚乳吸器,胚胎发育为紫菀型。并对一年蓬胚胎发育中的无融合生殖现象进行了讨论。

Embryological Studies in Erigeron annuus

The microsporogenesis,megasporogenesis,the development of male gametophyte,female gametophyte,double fertilization,embryo and endosperm of Erigeron annuus(L.) Pers.were examined.The anther is tetrasporangiate,the anther wall development follows the dicotyledonous type and comprises of an epidermis,endothelium,a middle layer and a single-layered tapetum,the epidermis degenerates,cells of endothelium persisted are columnar and with fibrous thick walls,the middle layer degenerates early after it formed,the tap...