This article describes the development of female gametophyte in Sedum rupestre L. New embryological information about the processes of megasporogenesis and megagametogenesis provided in this paper expand the current knowledge about the embryology of the studied species. S. rupestre is characterized by monosporic megasporogenesis and the formation of Polygonum-type embryo sac. The process of megasporogenesis is initiated by one megaspore mother cell, resulting in the formation of a triad of cells after meiosis and cytokinesis. The functional megaspore, which is located chalazally, is a mononuclear cell present next to the megaspore in the centre of the triad. Only one of the two non-functional cells of the triad is binucleate, which occur at the micropylar pole. In this paper, we explain the functional ultrastructure of the female gametophytic cells in S. rupestre. Initially, the cytoplasm of the gametophytic cells does not differ from each other; however, during differentiation, the cells reveal different morphologies. The antipodals and the synergids gradually become organelle-rich and metabolically active. The antipodal cells participate in the absorption and transport of nutrients from the nucellar cells towards the megagametophyte. Their ultrastructure shows the presence of plasmodesmata with electron-dense material, which is characteristic of Crassulaceae, and wall ingrowths in the outer walls. The ultrastructure of synergid cells is characterized by the presence of filiform apparatus and cytoplasm with active dictyosomes, abundant profiles of endoplasmic reticulum and numerous vesicles, which agrees with their main function-the secretion of pollen tube attractants. Reported data can be used to resolve the current taxonomic problems within the genus Sedum ser. Rupestria.

中文翻译：

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景天科景天雌配子体的发育、超微结构和细胞化学研究


本文描述了景天雌配子体的发育。本文提供的有关大孢子发生和大配子发生过程的新胚胎学信息扩展了有关所研究物种胚胎学的现有知识。 S. rupestre 的特征是单孢子大孢子发生和蓼型胚囊的形成。大孢子发生过程由一个大孢子母细胞启动，导致减数分裂和胞质分裂后形成三联体细胞。功能性大孢子位于合点处，是位于三联体中心大孢子旁边的单核细胞。三联体的两个非功能细胞中只有一个是双核的，出现在珠孔极。在本文中，我们解释了S. rupestre 雌配子体细胞的功能超微结构。最初，配子体细胞的细胞质彼此没有区别；然而，在分化过程中，细胞表现出不同的形态。反足体和助剂逐渐变得细胞器丰富且代谢活跃。反足细胞参与营养物质从珠心细胞向大配子体的吸收和运输。它们的超微结构显示存在具有电子致密材料的胞间连丝（这是景天科的特征），以及外壁中的壁向内生长。助细胞超微结构的特征是存在丝状器和具有活性网体的细胞质、丰富的内质网和大量的囊泡，这与其主要功能——分泌花粉管引诱剂相一致。报告的数据可用于解决景天属内当前的分类学问题。 岩蔷薇。