款冬的胚胎学

Embryology of Tussilago farfara (Asteraceae:Senecioneae)

系统报道了中藏药款冬大小孢子的发生、雌雄配子体发育和胚胎的发育过程。药壁发育双子叶型 ;绒毡层发育接近菊科中的“The Comosbipinnatus”型 ;成熟花粉为 3细胞型 ;单珠被 ,薄珠心 ,倒生胚珠 ;具发达的珠被绒毡层 ;胚囊发育 4孢子型 ,接近五福花 (Adoxa)型胚囊。受精作用属于有丝分裂前配子体融合类型。胚乳发育为核型。胚胎发育为紫菀型千里光变型。

The present firstly reports the development of microsporangium,male gametophyte,megasporogenesis,female gametophyte and embryogeny in Tussilago farfara ,a famous Chinese and Tibetan medicine.The anther is tetraporangiate and its wall development conforms to the dicotyledonous type.The tapetum is similar to “The Comos bipinnatus ” type of the Asteraceae.Cytokinesis is of the simultaneous type and microspore tetrads are mainly tetrahedral.Pollen grains are mainly 3 celled when shed.The ovule is unitegmic,tenuinucellate and anatropous with a developed endothelium.The development of embryo sac is of the “4 macrospore” type,similar to the Adoxa variation.Fertilization is of premitotic syngamy type.The development of endosperm conforms to the nuclear type and the embryogeny corresponds to the Senecio variation of the Aster type.The ecological and systematic significance of the embryological characteristics in this species is also discussed.