DIVERSITY OF THE VALVE ONTOGENY IN DIATOMS AND ITS RELATIONSHIP TO THE PHYLOGENY

从日本各地收集海洋和淡水硅藻。分离培养，为形态学观察和分子生物学实验提供材料。成熟瓣的扫描电镜观察揭示了一些新的结构在几个物种。蚧壳属中形成的裂孔和发育中的孢子周层。Eunotia的瓣体发育在中期阶段表现出与Araphid pennate diatoms的相似性。但在后期阶段与双针硅藻的个体发育相似。使用荧光标记剂，它被带到形成阀，可以区分核分裂后新形成的阀和核分裂前已经形成的阀。18S rDNA分析新揭示了拟十字链藻属、拟半甲藻属、Berkeleya属、双壁藻属、Luticola属、三种菱藻属和内菱形藻属的系统发育位置。在系统发育树中，没有显示出形态学上指出的拟扁蚜属与真蚜属的亲缘关系，而是与其他的海生属形成了单系。除硅藻科和真硅藻科的OUT数和系统发育分析结果表明它们之间的亲缘关系为机会主义外，硅藻高级别分类群的分支顺序反映了该分类群早期至中期个体发育相似性的顺序。5种硅藻的类硅质DNA序列具有较高的相似性，有望成为探索生物硅矿化能力起源的探针。

Marine and freshwater diatoms were collected from various places in Japan. They were isolated and cultured for the materials of morphological observations and molecular experiments. SEM observations of mature valves revealed some new structures in several species. In Cocconeis the forming valves and the developing perizonium of auxospore. The valve ontogeny of Eunotiashowed some similarity to araphid pennate diatoms in the middle stage of the development. But it showed ontogenetic similarity to biraphid diatoms in the late stages. Use of a fluorescent-label agent, which was taken into the forming valve, could distinguished the newly formed valves after nucleic division and valves already formed before nucleic division. The analyzes of 18S rDNA newly showed the phylogenetic position of Pseudostaurosira, Pseudohimantidium, Berkeleya, Diploneis, Luticola, three Cylindrofheca specis and Nitzschia palea. Close relationship between Pseudohimanthidium and Eunotia, that had been pointed out based on morphology, was not shown in the phylogenetic trees, as Pseudohimantidium formed monophyly with other araphid marine genera. Except for the relationship between Bacillariaceae and Eunotiaceae, which is an opportunist according to the number of OUT and the methods of phylogenetic analyzes, the branching order of the higher rank of diatom taxa reflected that of the ontogenetic similarities from the early to middle stages of the taxa. Sill-like DNA sequences decided in five diatoms showed the high similarity among them, impling its possibility to become a probe for exploring the origin of the biosilica mineralization ability.