| Project/Area Number |
12640653
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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 |
生物形態・構造
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
TAKASU Tokushiro Univ. of the Ryukyus, Tropical Biosohere Research Center, Proffesor, 熱帯生物圏研究センター, 教授 (50295341)
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| Co-Investigator(Kenkyū-buntansha) |
TOBE Hiroshi Kyoto Univ., Gradeuate school of Science, Proffesor, 大学院・理学研究科, 教授 (60089604)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Salt resistance / Viviparous germination / embryo / Rhizophoraceae / Mangrove plants |
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| Research Abstract |
The embryo of Rhizophora mucronata Lam. Shows viviparous germination which is characteristic for the mangrove plants, and the endosperm continues to grow and protrudes from the micropyle. We first used the term, aril for endosperm, but this ontogentetical study clarified that the protruded structure should be termed as endosperm. This protruded endosperm continues to develop in the carpel wall and finally protrudes from the carpel wall. The top portion of endosperm takes position between the hypocotyl of the embryo and carpel wall. In the early stage of seed development, the embryo grows by the nutrients supplied by the degeneration of endosperm cells. In the later stage, however, it grows by the nutrients resulted from the degeneration of seed coat cells. In the early stage of seed development, the endosperm cells grow absorbing nutrients produced by the degeneration of seed coat and endocarp cells. The generation of endosperm cells, seed coat cells and carpel wall cells begins by the disappearance of tonoplast in the vacuole. After this disappearance organelles in the cytoplasm become distorted and finally disperse as small particles in the cytoplasm. The plasma membrane in cells alive next to degenerating cells appears as quite active and highly undulated. The absorption of the nutrients by the degenerated materials seems to be by endocytosis. The salt contents in the endosperm increases gradually, or it is low when embryo is small and entirely surrounded by endosperm while it is high when the hypocotyle protrudes from the carpel wall and takes position between the carpel wall and hypocotyl. The above mentioned results support the working hypothesis that the endosperm protruded from the carpel wall has a function to protect the embryo portion inside the fruit from the attack by fungi and bacteria which might find the way into the fruit. The accumulation of high concentration salt acts as natural antibiotic.
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