肉苁蓉(Cistanche deserticola Ma.)胚胎学研究 Ⅰ.大、小孢子发生和雌、雄配子体形成

本文报道肉苁蓉大,小孢子发生和雌、雄配子体形成.主要结果如下;1)药壁发育为基本型,它由五层细胞组成,中层为二层,绒毡层分泌型,药室内壁未见纤维状加厚。2)小孢子母细胞相互分散,它们在减数分裂1时开始形成胼胝质壁。当小孢子从四分体中释放时,胼肤质壁消失。小孢子四分体为四面体型。其中有的四分体中的小孢子已分裂为二核。成熟花粉为二细胞型,花粉外壁较薄。3)倒生胚珠,单珠被和薄珠心。雌性孢原处于珠心表皮之下,为单细胞。孢原细胞直接起大孢子母细胞功能。随之,大孢子母细胞进行分裂形成直线型四分体。胚囊蓼型,由合点端大孢子发育而成。

The Studies on Embryology of Cistanche deserticola Ma. I. The mega-and microsporogenesis and the formation of male and female gametophytes

This paper reports the mega-and microsporogenesis and the formation of male and female game- tophytes in Cistanche deserticola. The main results are as follows: (1)Anther wall development con- forms to the dicotyledonous type. It consists of 5 layers of cells, There are two layers in the middle and the tapetum conforms to secretory type. There are no fibrous thickenings in the endothecium. (2)Mi- crosporocytes are scattered, and they begin to accumulate callose inn the meiosis I. When microspores are set free from tetrad, callose disappears at once, The microspore tetrads are of the tetrahedral type. The mature pollen grain belongs to the 2-celled type. The extine is thinner. (3)The ovule is anat- ropous, unitegenic and tenninucellar. The female archesporium differentiates from the single cell under the epidermis of nucellus. The archesporil cell directly plays a role of megaspore mother cell, and then the megaspore mother cells takes place to form a linear tetrad. The chalazal megaspore develops to form the embryo sac of polygonum type. The development of female gametophyte in Cistanche deserti- cola conforms to the monosporic type.