板栗(Castanea mollissima B1.)的胚胎学研究——(Ⅰ)胚珠、胚囊发育、受精和胚发生

报导了板栗胚囊发育、受精及胚发生的全过程。板栗子房6—9室,每室两个倒生胚珠着生于中轴胎座上。胚珠具双珠被、厚珠心。大孢子四分体线形排列,通常合点端的大孢子发育。蓼型胚囊。胚珠具宿存珠心柱。珠孔受精,受精后的胚囊产生侧向盲囊,初生胚乳核在盲囊底部形成,并很快在其中分裂产生核型胚乳。精卵融合为有丝分裂前型。合子斜向分裂产生基细胞和顶细胞,顶细胞经一次垂直分裂形成三细胞原胚,之后基细胞横分裂一次形成二细胞胚柄,该胚柄不久退化,胚发育应归属于柳叶莱型。成熟种子无胚乳。文中总结了板栗胚胎学过程的时间进程与外部形态相关特征的资料,并对山毛榉科植物胚胎学问题进行了讨论。

STUDY ON THE EMBRYOLOGY OF CHESTNUT (Castanea mollissima BL.) Ⅰ. THE DEVELOPMENT OF OVULES AND THE EMBRYO SAC, FERTILIZATION AND EMBRYOGENESTS

The present study describes the development of embryo sac, the process of the fertilization and embryogenesis in Castanea mollissima B1 The ovary consists of 6 - 9 locules; each llocule contains two anatropus, bitegmic and crassinucellar ovules. The chalazal megasporore of a linear tetrad develops into a Polygonum type embryo sac. A resistant nucellar column-postament remains protruding into the embryo sac from the chala-za until the early stage of the embryogenesis. The postament playes an important role in the transportation of nutrition from the chalaza to the embryo sac.And it sho ws a stronger PAS + reaction than other cells in the ovule. It was also observed that the central cells of the postament were different from other nucells in morphology.Fertilization occurs about 24 days after pollination,Syngamy is of the premitotic type. The formation of a caecum from a chalaz.al extension of the fertilized embryo sac was observed. Although the antipodals remain in site, two polar nuclei with a sperm and most of the cytoplasm of the central cell migrate into the caecum where triple fusion occurs. The primary endosperm nuclear forms in the bottom of the caecum and soon begins division. Endosperm is Nuclear but later become cellularThe first division of the zygote is slightly oblique, the embryogenesis in C.mollissima seems to be the Onagrad type.The relationship between morphological chracteristics of pistillate flowers and embryological events are given.With 4 plates and 36 figures