防风大、小孢子发生与雌、雄配子体发育的研究

Megasporogenesis and Gametophyte Microsporogensis as Well as Male and Female Gametophyte Development of Saposhnikovia divaricata

利用常规石蜡制片法研究了防风大、小孢子发生及其雌、雄配子体的发育过程.主要结果是: 1 小孢子母细胞减数分裂过程中的胞质分裂为同时型,小孢子四分体为四面体形; 2 成熟的花粉粒为三细胞型,具3个孔沟; 3 花药壁发育类型为双子叶型.花药壁由4层结构组成:最外层为表皮,其内分别为药室内壁、1层中层、绒毡层,绒毡层为分泌型; 4 防风的子房为2室,每室1胚珠,单珠被,薄珠心,倒生型胚珠.大孢子母细胞经减数分裂形成线形排列的4个大孢子,合点端大孢子具功能; 5 大孢子发生过程中,具有多个孢原细胞及多个大孢子母细胞的现象,但通常只有一个大孢子母细胞能继续发育; 6 胚囊发育属于蓼型; 7 防风的花为极端的雌雄蕊异熟,雄蕊的发育早于雌蕊的发育.

The conventional paraffin section was adopted to study megasporogenesis and gametophyte microsporogensis as well as male and female gametophyte development of Saposhnikovia divaricata( Turez.)Schischk. The results were as follows :(1)In microsporocyte meiosis , the cytoplasm division was of simultaneous types and the microsporocyte tetrad was tetrahedral; (2)The mature anthers belonged to a three-cell type and had three colporates;(3)The development of the anther wall belonged to a dicotyledonous type. The pollen wall consisted of four structural layers, epidermis, endothecium, one middle layer and tapetum from outer to inner. Tapetum belonged to a secretary type.(4)The ovary had two chamber each of which had one ovule that was unitegmic, tenuinucellate and anatropous. After meiosis, the megasporocytes divided into four linearly arrayed megaspores the ones of which at chalazal end usually had functional capacity. (5)In the formation of the megaspores , several sporogonium and several megaspores might appear but only one megasopore of them continued to grow and develop.(6)The embryo sac belonged to a Pangianum type in its development.(7)The stamen and pistil of Saposhnikovia divaricata(Turez.)Schischk.flowers matured in an extremely asynchronous manner, the stamen developing earlier than the pistil.