| 摘要: |
| 于1999 年7 月在湖北省仙桃市湿润土壤中采得一种鞘藻, 经培养和电镜观察, 发现该株鞘藻营养生长主要依赖位于丝状体最上面的细胞分裂, 分生出的子细胞在该细胞亚顶端的胞壁破裂点掀开一个帽子, 此帽子便附着于细胞侧壁上, 这在鞘藻属中为首次报道, 与2000 年12月在武汉纸坊青龙山水库采得的一种毛鞘藻的基细胞也附着相同的帽子结构。观察结果表明, 该属基细胞亦具有明显的居间分裂能力。在观察这两属营养细胞居间分裂的同时, 详细报道了这一种特殊的细胞分裂——顶端分裂, 详细比较了这两属的营养细胞分裂方式, 并对其分裂方式的机制进行探讨。结果表明, 这两属细胞在细胞分裂方式上有极为亲密的亲缘关系, 但毛鞘藻属更复杂、独特的营养细胞分裂显示它的进化地位比鞘藻属高。 |
| 关键词: 鞘藻属, 毛鞘藻属, 居间分裂, 顶端分裂, 冠状环纹结构, 帽子结构 |
| DOI： |
| 分类号: |
| 基金项目:中国科学院青年科学家小组创新项目, 1999051 号; 青藏高原及其邻近地区植物区系及分布格局研究项目, KSCX2-1-06B 号; 中国科学院水生生物研究所创新领域前沿项目资助, 220104 号 |
附件 |
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| A PRELIMINARY INVESTIGATION OF OEDOGONIUM AND BULBOCHAETE BASED ON COMPARATIVE STUDIES OF VEGETATIVE CELL DIVISION |
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LUO Wei1,2, LIU Guo-Xiang3, HU Zheng-Yu3
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1.Institute of Hydrobiology , The Chinese Academy of Sciences;2.Graduate School , The Chinese Academy of Sciences;3.Institute of Hydrobiology, The Chinese Academy of Sciences
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| Abstract: |
| Cell division in the Oedogoniales is unusual and a characteristic of the order. Along with the nucleolus division, the formation of a ring adjacent to the inner wall in the upper portion of the cell is initiated. The ring gradually becomes incrassation following the development. A direct consequence of this rupture wall and ring expansion, the typical feature of mediacy division, is the formation of the caps so characteristic of this group of algae. However, some cells at the top of the filaments have the capability of another remarkable cell division which is known as the apical division resulting in one cover-like cap being pulled to one side of the filament along with the development of the division.
We collected the samples of Oedogonium from Xiantao City, Hubei Province in Dec. , 2000. During the unialgal culture, we observed the special apical cell division in the species through the microscope and scanning electronic microscope. It is the first report about the special apical cell division in the genus of Oedogonium. This report presents the resemble faces and differences on both the mediacy division and the apical division in the two genera. Oedogonium is an unbranched filamentous alga, which always exhibits such typical division and principal features. We also collected the samples of Bulbochaete in one rice paddy from Qinglongshan Reservoir, Zhifang Area, Wuhan City, Hubei Province. Cell division in the genus Bulbochaete closely resembles that of Oedogonium, particularly in the involvement of a ring in cell elongation and the method of cross wall formation, which indicates intimate phylogenetic relationship in the two genera. But there are subtle differences in the morphology of their cell wall. The basal cell of Bulbochaete is apparently capable of many successive mediacy division after an apical division which produces the special cap sticking to the cell wall. Another characteristic of the Bulbochaete is the numerous, colorless hairs; these single cells are either terminally situated ( sometimes in pairs) on the main axis or branches or else at potential branch points at the apical end and to one side of vegetative cells. And some species of the Bulbochaete which the main axis is very conspicuous and branches are not obvious chiefly depend on the mediacy growth. The more complex vegetative morphology of Bulbochaete compared with Oedogonium is fairly easily explicable. Consequently, such the features as the differentiation of hair cell and the subsequently creation of branches show that the genus of Bulbochaete is a more advanced group than the Oedogonium in the evolution. |
| Key words: Oedogonium, Bulbochaete, Mediacy division, Apical division, The ring structure, The cap structure |
