| Project/Area Number |
16570077
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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 |
Biodiversity/Systematics
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| Research Institution | Hiroshima University |
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Principal Investigator |
YAMAGUCHI Tomio Hiroshima University, Graduate School of Science, Associate Professor, 大学院理学研究科, 助教授 (60244290)
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| Co-Investigator(Kenkyū-buntansha) |
TSUBOTA Hiromi Hiroshima University, Graduate School of Science, Associate Professor, 大学院理学研究科, 助教授 (10332800)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2006: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2005: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2004: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Bryophyte / Systematics / Speciation / Islands / 蘚苔類 / シラガゴケ科 |
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| Research Abstract |
Gametophyte development, phylogeny and speciation of bryophytes was studied using interisland species. Leucobryum boninense is an enigmatic species distributed in southeast China and islands of the northwestern Pacific and is the only species of Leucobryum known from the Bonin Islands which are typical oceanic islands. Molecular phylogenetic analysis using internal transcribed spacer (ITS) of nrDNA sequences was performed to resolve phylogenetic relationships among geographically isolated populations of L. boninense and its related species. The analysis showed that L. boninense was divided into two distinct clades, which correspond to geographical regions: an oceanic island clade (Bonin clade) and a continental region clade (Ryukyu clade). These two clades were also distinguished from each other by the ratio of the length of the prorate apex region to the whole leaf length, ecological preference, and the colony habit. Plants of the Ryukyu clade proved to correspond to L. scaberulum, previously treated as a synonym of L. boninense. Molecular and morphological evidence strongly suggests that L. boninense is endemic to the Bonin Islands, and that L. scaberulum should be treated as a distinct species. Our studies on bryophytes including Leucobryum spp. proved that endemism of bryophytes on the oceanic islands might be result of a allopatric speciation.
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