VALVE MORPHOGENESIS IN THE PENNATE DIATOM ACHNANTHES COARCTATA
VALVE MORPHOGENESIS IN THE PENNATE DIATOM ACHNANTHES COARCTATA
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DOI：
10.1111/j.0022-3646.1984.00563.x
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发表时间：
1984-12
影响因子：
2.9
通讯作者：
J. A. Boyle;J. Pickett-Heaps;D. B. Czarnecki
中科院分区：
文献类型：
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作者：
J. A. Boyle;J. Pickett-Heaps;D. B. Czarnecki
羽状硅藻Achnanths coarctata(BréB.in W.Sm.)的有丝分裂和瓣膜形态发生格伦。都被描述了。胞质分裂后，靠近细胞一侧的子核及其微管中心均可见。每个新的管状二氧化硅沉积小泡(SDV)位于中心，形成一根贯穿整个细胞长度的肋骨。然后，每个MC围绕其核心迁移，并将自己直接定位在新的SDV附近。增大的硅膜及其相关的MC、核、微管(MT)和微丝(MFS)出现在子细胞的镜像中。这两个SDV很快就会在第一个纵向肋骨旁边形成第二个纵向肋骨；肋骨之间的缝隙最终成为未来的中缝裂缝。MC、MTS和细胞核与每个裂隙相联系。然而，在子代细胞中，瓣膜分泌机制的后续行为现在变得非常不同。在将形成石墨瓣膜的细胞中，硅膜在MFS的两侧，在乳沟上方向两个方向横向扩张。在扩张的SDV内，硅质继续分泌，最终形成成熟瓣膜的结构，在此阶段，中缝裂隙被描绘成其他石墨硅藻的轮廓。然而，在另一个子细胞中，MC及其MTS退出硅膜，SDV横向穿过分裂沟，直到双肋位于细胞的角落。随着二氧化硅被分泌到这个不断扩大的SDV中，中缝裂缝完全被填满。因此，这个瓣膜在成熟时缺乏中缝，其对称性与在另一个子细胞中形成的瓣膜完全不同。将这些事件与所描述的其他硅藻的形态发生过程进行了比较。
Mitosis and valve morphogenesis in the pennate diatom Achnanthes coarctata (Bréb. in W. Sm.) Grun. are described. After cytokinesis, both daughter nuclei and their microtubule centers (MCs) are found near one side of the cell. Each new tubular silica deposition vesicle (SDV) arises centrally, forming a single rib running the length of the cell. Each MC then migrates around its nucleus and positions itself directly adjacent to the new SDV. The enlarging silicalemmas with their associated MCs, nuclei, microtubules (MTs) and microfilaments (MFs) appear in mirror image in the daughter cells. Both SDVs soon generate a second longitudinal rib alongside the first; the gap between the ribs ultimately becomes the future raphe fissure. The MC, MTs and nucleus are associated with each fissure. However, the subsequent behavior of the valve secreting machinery now becomes quite different in the daughter cells. In the cell that will form a raphid valve, the silicalemma, flanked by MFs, expands laterally in both directions over the cleavage furrow. Within the expanding SDV, silica secretion continues, eventually generating the structure of the mature valve, and during this phase the raphe fissure becomes delineated as in other raphid diatoms. In the other daughter cell, however, the MC and its MTs withdraw from the silicalemma, and the SDV moves laterally across the cleavage furrow until the double rib is at the corner of the cell. As silica is secreted into this expanding SDV, the raphe fissure completely fills in. This valve, therefore, lacks a raphe when mature and has a symmetry quite different from that of the valve formed in the other daughter cell. These events are compared with the course of morphogenesis described for other raphid diatoms.