| Project/Area Number |
04640639
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物形態・分類学
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| Research Institution | Joetsu University of Education |
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Principal Investigator |
OGAWA Sshigeru Joetsu University of Education, Department of School Education, Assistant Professor, 学校教育学部, 助教授 (40194435)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1992: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Boergesenia / Bryopsis / Coenocytic green algae / Green algae / Mitosis / Ultrastructure of mitosis / Vegetative cell / ミル目 |
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| Research Abstract |
Ultrastructural features of cell division in vegetative cells have been recognized as valuable taxonomic characters in elucidating the phylogenetic affinities among green algae. But, the coenocytic algae in the green algae class Ulvophyceae are poorly represented. The present research is attempted to obtain more information on mitoses in vegetative cells of the coenocytic algae of the Ulvophyceae. In the present research, the siphonocladalean alga Boergesenia forbesii and the codialean alga Bryopsis plumosa were used, because their vegetative cells could readily be cultivated unialgally under artificial conditions.
In Boergesenia forbesii, the mitotic spindle was centric and closed. The polar region of nuclear envelope of the metaphase nucleus did not open. The anaphase separation of sister chromosomes was asynchronous. Kinetochores were evident on chromosomes. Nucleolar materials persisted within dividing nuclei. Almost all of these features of mitosis in B.forbesii are common to the mitoses in some cladophoralean species as well as in some siphonocladalean species, supporting a recent proposal that the Siphonocladales and the Cladophorales should be united into a single order.
In Bryopsis plumosa, the mitotic spindle was closed and acentric. The separation of sister chromosomes at anaphase was synchronous. Chromosomes did not have evident structured kinetochores. Nucleolar materials were present within dividing nuclei. With respect to the ultrastructural features of mitosis, B.plumosa resembles the caulerpalean and the dasycladalean algae.
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