1995 Fiscal Year Final Research Report Summary
Phylogeny and Organ-phylogenesis of Primitive Vascular Plants
| Project/Area Number |
06454029
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
系統・分類
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KATO Masahiro The University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (20093221)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Psilotum nudum / stem / apical cell / Oleanodropsis / homology / phylogenesis / Selaginella / microphyllous leaf |
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| Research Abstract |
1. Psilotum nudum, a rootless primitie vascular plant of a striking organographic simplicity, has leaf-and capless, subterranean rhizomes. The rhizomes show irregular branching, due to a low degree of organization of the apical meristem. about a half of derivative cells of the apical cell produce apical cell precursors, of which roughly a half become daughter apical cells, wihle the other half differentiate to somatic cells. It is in contrast to the apical meristem of the other vascular plants with a close correspondence between apical cells and branching. The aerial stem of Psilotum nudum has the same organization of apical meristem as that of the other plants. The rhizome compares only with an ancient axial organ calle telome.
2. Oleandropsis is a genus unique in the radial structure of rhizomes within Polypodiaceae which have dorsiventral rhizomes. A DNA base sequence analysis shows that Oleandropsis is placed within the Selliguea group in the family. It is suggested that the radial rhizomes were derived from the dorsiventral ones, in a reverse direction to the genearal evolutionary trend in the ferns.
3. A modified mold-cast method was applied to examine the development of microphyllous leaves of Selaginella, which are believed to be derived from enations on telomes. Surgical experiments will be attempted for elucidating the phylogenesis of microphyllous leaves.
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