| Project/Area Number |
09440272
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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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 Tsukuba |
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Principal Investigator |
HORI Terumitsu Institute of Biological Sciences, University of Tsukuba, Professor, 生物科学系, 教授 (90057563)
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| Co-Investigator(Kenkyū-buntansha) |
NOZAKI Hisayoshi Department of Biological Sciences, Graduate School of Science, University of Tokyo, Associate Professor, 大学院・理学系研究科, 助教授 (40250104)
MIYAMURA Shin-ichi Institute of Biological Sciences, University of Tsukuba, Assistant Professor, 生物科学系, 講師 (00192766)
INOUYE Isao Institute of Biological Sciences, University of Tsukuba, Professor, 生物科学系, 教授 (70168433)
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| Project Period (FY) |
1997 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥13,000,000 (Direct Cost: ¥13,000,000)
Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1999: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1998: ¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1997: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | male gamete / sperm / bryophyte / peridophyte / green alga / gymnosperm / 藻類 |
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| Research Abstract |
This project was conducted to evaluate the biological significance of the spiral architecture of sperms in sexual reproduction of plants which are assigned to the land-plant lineage.
(1) All sperms produced by plants belonging to the land-plant evolutional lineage are fundamentally spiral either in their external architecture or intracellular organization, or both. The most ovbious features are found in their coiled streamlined body of sperm cell and spiral arrangement of flagella on the surface of cell body. The internal ones are reflected on the intracellular arrangement of various cell organelles, including cell nucleus, anterior giant mitochondrion, and basal bodies.
(2) Biflagellate sperms are produced in charophytes, mosses, liverworts, and a few lycophytes.. In biflagellate sperms two flagella are inserted at the cell anterior and their basal bodies are positioned slightly downward from the cell tip, thus resulting in an asymmetrical profile of cell architecture. Two basal bodies
… More
are monomorphic and parallel, staggered in an anterior to posterior fashion in contrast to those of sperms of other photosynthetic organisms.
(3) Multiflagellated sperms are found in most ferns and a few gymnosperms, including Ginkgo and cycads. In multiflagellated sperms flagella and their basal bodies are arranged in spiral fashion with several rows. The cell body coils to the left when viewed from the anterior. Basal bodies are distributed on the MLS in different manners, indicating the difference of their role in swimming movement.
(4) The sperm that have such structural features only swimm forward in spiral fashion, but does not have ability of back-swimming to avoid material as those of green algal swarmers of other evolutionary lineages.
(5) The coiled structure of body and spiral arrangement of flagella may effectively work to drill down through the neck and ventral canals of the archegonium in the archegoniate fertilization, but significance of these morphological characteristics in male gametes of some charophytes, including Coleochaete, Klebsormidium, is uncertain. Less
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