Auxosporulation, morphology of vegetative cells and perizonium of Fallacia tenera (Hust.) D.G. Mann (Bacillariophyceae)
Auxosporulation, morphology of vegetative cells and perizonium of Fallacia tenera (Hust.) D.G. Mann (Bacillariophyceae)
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DOI：
10.11646/phytotaxa.164.4.3
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发表时间：
2014-04
期刊：
影响因子：
1.1
通讯作者：
Yuhang Li;Hidekazu Suzuki;T. Nagumo;J. Tanaka
中科院分区：
文献类型：
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作者：
Yuhang Li;Hidekazu Suzuki;T. Nagumo;J. Tanaka
从日本河口的表层沉积物中采集了细剑剑水蚤标本。粗培养时产生芽孢。详细观察了营养细胞和孢子的形态结构。营养细胞有一个H形叶绿体。纹被两个凹陷的外侧胸骨内部和部分覆盖的细孔锥的外表面中断。侧胸骨和多孔锥形成两条弯曲的纵行管，通过终裂两侧的开口孔与外界相通。这种特征的组合是Fallacia属所独有的。扣带由三条带组成，即一个开放的瓣杯和两个相对较薄的胸膜。这两个胸膜可以通过它们的舌的形状来区分。第二带的舌部呈三角形，而第三带的舌部呈弧形。根据Geitler分类法，其孢子发育类型为IA1a型。两对配子囊形成两个异配子。在配子囊的囊壁中，经反式生理异配形成两个孢子。孢子周层由一组横带和五条纵带组成。初级横带的宽度约为次级横带的两倍。在孢子的两端和初生横带的表面有圆形的珠状鳞片。初级纵带末端尖锐，两侧为次级纵带。每侧有两条次级纵带。所有纵带均位于横带正下方。对Fallacia和Pseudofallaica的形态进行了比较，并对Fallacia的分类地位进行了讨论。还讨论了Tenera。
Specimens of Fallacia tenera were collected from the surface sediment at in a river estuary in Japan. Auxosporulation occurred in a rough culture. Morphological structures of vegetative cells and auxospores were observed in detail. The vegetative cells have one H-shaped chloroplast. The striae were interrupted by two depressed lateral sterna internally and partly covered by a finely porous conopeum on the external surface. The lateral sterna and porous conopea formed two more or less curved longitudinal canals connecting with the exterior via opening pores on both sides of a terminal fissure. This combination of characteristics is unique to the genus Fallacia . The cingulum was composed of three bands, such as an open valvocupula and two comparatively thin pleurae. The two pleurae could be distinguished by the shape of their ligulae. The second band had a triangular ligula, whereas the ligula of the third band is arc-shaped. The auxosporulation was type IA1a in Geitler’s classification. Two paired gametangia formed two anisogametes in each of them. Two auxospores formed in the thecae of the gametangia after a trans physiological anisogamy. The perizonium of the auxospore consisted of a set of transverse bands and five longitudinal bands. The primary transverse band was about twice wider than the secondary ones. The circular incunabular scales were present on the two terminals of the auxospore and on the surface of the primary transverse band. The primary longitudinal band had an acute terminal and was flanked by secondary longitudinal bands. Each side had two secondary longitudinal bands. All longitudinal bands were immediately beneath the transverse bands. Morphological comparison between Fallacia and Pseudofallaica , and the taxonomic position of F. tenera is also discussed.