The origin and morphological evolution of th outer integument of angiosperms.
| Project/Area Number |
07640935
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
系統・分類
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| Research Institution | Tamagawa University |
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Principal Investigator |
KANEKO Makoto Tamagawa University, Faculty of Agriculture, Assistant Professor, 農学部, 助教授 (10138604)
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| Co-Investigator(Kenkyū-buntansha) |
IMAICHI Ryoko Tamagawa University, Faculty of Agriculture, Professor, 農学部, 教授 (60112752)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | primitive angiosperms / outer integument / comparative morphogenesis / anatropous ovule / orthotropous ovule / Laurales / paleoherb / Glossopterids / 胚珠 / 内珠皮 / テローム / 珠孔 / シダ種子類 / 杯状体 |
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| Research Abstract |
Bitegumic, as well as anatropous ovules are the most common in and unique to angiosperms. Comparative morphogenesis of the outer integument was performed in several taxa of Magnoliales and Laurales using scanning electron microscope. It aimed to clarify the origin and morphological evolution of the outer integument in the angiosperms. The outer integuments of Winteraceae, Degeneriaceae, Eupomatiaceae, Atherospermataceae, and Lactoridaceae arose as semi-annular outgrowth interrupted on the concaveside of the funiculus and then becomes hood-shaped. In Magnoliacea, Monimiaceae and Trimeniaceae, however, the funicular outgrowth intervenes in the gap of the hood-shaped outer integument on the concave side of the funiculus. This fact favors one hypothesis that the inner integument was derived from a telomic assembly at the origin of gymnosperms and the outer integument from a leaf-like organ at the origin of angiosperms. The outer integument is compared with the ovuliferous sporophylls of the glossopterid and caytonialean seed ferns.
In case of semi-anatropous ovules of Himantandraceae and of Myristicaceae, the funicular outgrowth on the concave side of the funiculus was formed so early that the hood-shaped outer integument was not clearly seen from the surface. The outer integument appears to be initiated as on oblique ring-like outgrowth from the beginning as a result of congenital fusion between the hood-shaped outer integument and the funicular outgrowth. The orthotropous ovule of Zippelia (Piperaceae, paleoherb) was shown to arise as entire cup-shaped outgrowth from the beginning. There is no indication here that the outer integument is originally in hood-shaped. Developmental observation does not show the cup-shaped or oblique ring-shaped outer integument was formed as a result of ontogenetic fusion between the hood-shape outer integument and tha funicular outgrowth on the concave side of the funiculus.
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Report
(3 results)
Research Products
(3 results)
