Ellerbeckia arenaria (Bacillariophyceae): formation of auxospores and initial cells
Ellerbeckia arenaria (Bacillariophyceae): formation of auxospores and initial cells
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Ellerbeckia arenararia（硅藻纲）：辅助孢子和初始细胞的形成
DOI：
10.1080/09670260110001735468
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发表时间：
2001
影响因子：
2.4
通讯作者：
R. Crawford
中科院分区：
文献类型：
--
作者：
A. Schmid;R. Crawford
利用光镜和电镜研究了淡水链状硅藻沙芽藻（Ellerbeckia arenaria forma arenaria）的辅助孢子和初始细胞的发育。副孢子母细胞是通过营养性形成（孤雌生殖）还是通过自交配形成仍然是一个值得推测的问题。因为在我们的材料中没有检测到精子发生的迹象，我们排除了卵婚。进一步的发育包括原生质体从外胚层缩回，形成一个无特征的硅质帽，在其自由表面有一个中央开口。该帽的同源性和功能仍不确定。在细胞的另一端，原生质体在其进一步发育过程中始终紧紧地附着在下瓣上。这种下瓣总是有一个凹瓣面。当细胞仍被包围在母细胞壁内时，一层有机壁开始形成，其中包含多层重叠的小二氧化硅鳞片，并允许副孢子膨胀，从而打破硅帽和硅带。鳞片的外表面和内表面可以从形态学上区分出来。初始阀门形成在鳞片内部，与母链呈斜角。最初的外胚层瓣总是面对着副孢子母细胞的下胚层，并且在营养细胞中已经表现出异胚层瓣的成分。讨论了这些观测结果在生态学和系统发育方面的意义。配制出砂螺（Moore ex Ralfs） R. M. Crawford和砂螺（brown ex Schmidt） R. M. Crawford组合。
The development of auxospores and initial cells of the freshwater chain-forming diatom Ellerbeckia arenaria forma arenaria was studied using light and electron microscopy. Whether the auxospore mother cell is formed vegetatively (parthenogenesis) or through autogamy is still a matter for speculation. Because no signs of spermiogenesis could be detected in our material, we exclude oogamy. Further development involves retraction of the protoplast from the epivalve and the formation of a featureless siliceous cap with a central opening on its free surface. The homology and function of this cap remain uncertain. At the other end of the cell the protoplast remains tightly attached to the hypovalve throughout its further development. This hypovalve always has a concave valve face. An organic wall bearing many layers of overlapping, small silica scales begins to be formed while the cell is still enclosed within the mother cell wall, and allows the auxospore to swell, thus breaking the siliceous cap and girdle bands. External and internal surfaces of scales can be distinguished morphologically. Initial valves are formed internal to the scales at an oblique angle to the parent chain. The initial epivalve always faces the hypotheca of the auxospore mother cell, and the initial valves already show elements of the heterovalvy manifest in the vegetative cells. The significance of the observations in terms of ecology and phylogeny is discussed. The combinations Ellerbeckia arenaria (Moore ex Ralfs) R. M. Crawford, and E. arenaria forma teres (Brun ex Schmidt) R. M. Crawford are made.