Sporogenesis and gametogenesis in Agapanthus praecox Willd. orientalis (Leighton) Leighton and their systematic implications
Sporogenesis and gametogenesis in Agapanthus praecox Willd. orientalis (Leighton) Leighton and their systematic implications
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百子莲的孢子发生和配子发生。
DOI：
10.1007/s00606-010-0280-7
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发表时间：
2010-08-01
影响因子：
1.9
通讯作者：
Shen, Xiao-Hui
中科院分区：
文献类型：
--
作者：
Zhang, Di;Zhuo, Li-Huan;Shen, Xiao-Hui
小孢子发生和大孢子发生以及雌、雄配子发生均为首次报道。结果表明：花药壁发育为双子叶类型，由4层组成：表皮、药室内壁、1~2层中层和分泌绒毡层。脱落时，药室内壁形成纤维增厚。小孢子发生过程中的连续胞质分裂形成交叉的四分体小孢子。当花药开裂时，椭圆形的花粉粒为2细胞，单硫化的花粉延伸至极地；花粉纹饰为凹坑和网状。卵巢上位，三室，中轴胎盘。胚珠倒生，双珠被，细珠心。珠心表皮下的孢原细胞直接起着大孢子母细胞的作用。大孢子母细胞的连续胞质分裂通常形成T形四分体，四分体的合点端大孢子发育成何首乌类型的胚囊。讨论了长春花属胚胎学特征的系统学意义。
Micro- and megasporogenesis as well as male and female gametogenesis in genus Agapanthus are reported for the first time. The results are as follows: The anther wall, whose development is of dicotyledonous type, consists of four layers: the epidermis, the endothecium, one or two middle layers, and the secretory tapetum. Fibrous thickenings are developed in the endothecium when shed. Successive cytokinesis during microsporogenesis results in a decussate tetrad of microspores. Ellipsoidal pollen grains are 2-celled when anthers dehisce, with monosulcate extending to polar area; pollen ornamentation is pitted and reticulate. Ovary is superior and trilocular, with axial placenta. The ovule is anatropous, bitegmic, and tenuinucellate. The archesporial cell below nucellus epidermis functions directly as the megasporocyte. Successive cytokinesis in the megasporocyte usually produces a T-shape tetrad, and the chalazal megaspore of the tetrad develops into a Polygonum-type embryo sac. The systematic significance of embryological characters of Agapanthus is discussed.