| Project/Area Number |
10440230
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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 |
生態
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| Research Institution | HOKKAIDO UNVERSITY (2000)
The University of Tokyo (1998-1999) |
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Principal Investigator |
OHARA Masashi Hokkaido Univ., Grad.School of Env.Earth Sci., Asso.Prof., 大学院・地球環境科学研究科, 助教授 (90194274)
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| Co-Investigator(Kenkyū-buntansha) |
TAKADA Takenori Hokkaido Tokai Univ., Dept.of Intl.Cult.Rel., Prof., 国際文化学部, 教授 (80206755)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥11,400,000 (Direct Cost: ¥11,400,000)
Fiscal Year 2000: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1999: ¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1998: ¥5,200,000 (Direct Cost: ¥5,200,000)
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| Keywords | genetic variation / genus Trillium / demography / forest fragmentation / long-term census / understory herb / 森林孤立化 / 交配様式 / 遺伝的多様性 |
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| Research Abstract |
In order to assess the effects of forest fragmentation on genetic components of understory herbs, reproductive, demographic and genetic characteristics of two Trillium species were studied.
Investigation on seed production of, self-incompatible and insect-pollinated, T.camtschatcense populations in eastern Hokkaido revealed that large populations and/or continuous populations surrounded with abundant forest series produced a higher number of seeds than small and isolated populations. The levels of genetic diversity, inbreeding coefficient, and the patterns of local population structure were also assayed using allozyme electrophoresis (6 enzymes and 11 loci). The log of population size had positive and significant relationships with the percentage of polymorphic loci and allelic richness. In addition, all alleles which were not observed in small populations were rare.
In order to forecast the future population size under stochastically varying environment, population dynamics of T.apetalon were investigated by application of the transition matrix model to the long-term census data and by breeding experiments in the field. The matrix model demonstrated that mortality rates of small individuals, such as seedlings and plants at the one-leaf sterile stage, were very high and that the probabilities for transition from the one-leaf stage to the three-leaf stage and from the three-leaf stage to flowering were very low. Although T.apetalon had a substantial capacity both for inbreeding and outbreeding, inbreeding was predominant. Furthermore, subsequent resource limitation allowed only acertain level of fecundity, regardless of the original fertilization level.
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