柽柳大、小孢子发生和雌、雄配子体发育的观察

Observations on megasporogenesis, microsporogenesis and development of female and male gametophytes of Tamarix chinensis(Tamaricaceace)

利用常规石蜡制片技术,对柽柳(Tamarix chinensis Lour.)的大、小孢子发生及雌、雄配子体发育过程进行了观察.主要结果如下:(1)花药壁由五层细胞组成,从外向内分别为表皮、药室内壁,两层中层和绒毡层.药壁的发育属于基本型.绒毡层为分泌型.(2)孢原细胞为多孢原起源.小孢子母细胞减数分裂过程中的胞质分裂为连续型,形成的四分孢子为四面体型;同一药室的小孢子母细胞减数分裂几乎完全同步.(3)成熟花粉粒为2细胞型,具3个萌发孔.(4)柽柳为三心皮构成的单室复子房,每子房具有10～20个胚珠,基底胎座,胚珠为双珠被、厚珠心、倒生型.大孢子母细胞减数分裂形成1+3排列的4个大孢子,4个大孢子全部参与胚囊的形成.(5)胚囊发育为贝母型,反足细胞在胚囊成熟时充分发育.(6)同一朵花中,前期雄蕊的发育早于雌蕊的发育,后期当花粉成熟时,雌配子体也达到成熟,雌雄蕊发育趋于同步.

We did a series of studies on megasporogenesis, microsporogenesis and the development of female and male gametophyte of Tamarix chinensis by means of traditional paraffin wax sections. The relationships between floral bud size and development of stamen and pistil are also observed. The main results are as follows: Several rows of hypodermal archesporial cells differentiate in each lobe of young four-lobed anther. The wall of anther consists of five layers: epidermis, endothecium, two middle layers and tapetum from out to inside, which belongs to basic type. Tapetum cell is of secretory type. Cytokinesis of microsporocyte meiotic division is of simultaneous type and the tetrads are tetrahedral. Meiotic division of microsporocyte develops synchronously in each microsporangium of an anther. The pollen grains are three-colpate and two-celled at the dispersal stage. There is an unilocular ovary that contains three fused carpels in one flower and each ovary has 10~20 ovules. Ovules occur at the base of ovary, which is basal placentation. The ovule is bitegmic, crassinucellate and anatropous. The megaspore mother cell undergoes meiotic divisions, and the development of the embryo sac is of Fritillaria type. In mature embryo sac, antipodal cells are well developed. Early in floral bud, archesporial cells of anther differentiate earlier than that of ovule. When the stamen matures, the pistil matures either. They are nearly synchronous at this time.