金色狗尾草的大、小孢子发生及雌、雄配子体发育

Mega-and Microsporognesis and Development of Femal and Male Gametophyte in Setaria glauca

金色狗尾草花药壁分四层，即表皮、内壁、中层、绒毡层。表皮细胞在花粉发育过程中始终沉积呈颗粒状小体。绒毡层属腺质型。小孢子母细胞在减数分裂过程中，胞质分裂属连续型，非偶见有染色质穿壁现象。生殖细胞壁在初期具纤维素。成熟花粉为3细胞，内贮大量淀粉粒。金色狗尾草胚珠具观珠被，珠孔由内珠被形成，外珠被有一突起伸向花柱。近珠孔端珠心表皮细胞一般有4个特化，体积较大，偶见2、3或5个。在胚囊成熟期，特化细胞的细胞壁较厚，内贮淀粉颗粒。大孢子母细胞减数分裂形成直线型四分体。合点端功能大孢子发育为单核胚囊，并经三次核的有丝分裂形成7细胞（8核）的蓼型胚囊。

The anther wall of Setaria glauca consists of four layers: epidermis, endothecium ,mid-dle layer and tapetum. Accumulation of granular bodies was found in the epidermic cells during the de-velopment of pollen. The tapeturn corresponds to glandular type. The cytokinesis of hacrospore mother cells during meiosis conforms to successive type. The intercellular migration of chromatin was observed atthis hme occasionally. The early generative cell wall contains cellulose and the 3-celled Pollen grain ac-cumulates starch grains at its mature. The bitegmic and crassinucellate ovule is anatropous. The outer in-tegument has a protrusion extending to the base of style and the inner integument forms a micropyle. Thefour cells, occasionally two, three or five, of the nucellar epidends abutting the microphle enlarge con-siderably during the development of female gametophyte, thicken their wall gradually and store starchgrains at the stage of mature embryo sac. The megaspore tetrad is linear and the chalazal megaspore de-velops into uni-nucleate embryo sac. Then the uni-nucleate embryo sac forms 7-celled or 8-nucleate em-bryo sac of polygonum type following its three times division successively.