| Project/Area Number |
05660157
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
林学
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
WATANABE Naoaki Tokyo University, of Agric.& Technol AGRICULTURE,Assistant Professor, 農学部, 助手 (10143637)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1994: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1993: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Armillaria / Water activity / Water potential / Rhizomorph / Laboratory infection |
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| Research Abstract |
Young plantation stands of Chamaecyparis obtusa and other forests were investigated on Armillaria disease damages and its distribution. More than three biological species were found in a seven-year-old cypress stand. Armillaria mellea s.str had mainly colonized upper area near ridge in the damaged stand. The infection of a mature Eucalyptus stand was newly recorded in Japan.
Bound in roots and rubber bands, seven strains of A.mellea inocula by culturing on small brach had achieved successful infection. But other 37 strains occurred no infection. In comparison with Pressure-Volume curves of a control seedling, tugor loss point of a diseased seedling with abundant rhizomorph increased a little.
In laboratory inoculation experiments, no infection was occurred among eighteen strains, even Armillaria mycelia had growed around a seedling stem or had fully mixed with roots in Murashige-Skooge agar media with 2% malt extract. The effects of water potential on the mycelial growth and rhizomorph formation of eight strains was studied. Lower limit of the water potential for mycelial growth were more than -5.9MPa among above strains. Somewere more than -4.5MPa. A strain which mainly distributed wet site could also grow at lower water potential. It means that this strain adapted to grow for lower water activity circomstances such as in wet wood decaying, not for dry air environment. Most strains formed crustose colony or rhizomorph at higher water potential above -1.2MPa. It is clear that rhizomorph formation simply depends on water activity of substrates but on nutritional condition. Two strains of A.mellea s.str.formed rhizormorph at -1.8Mpa and -1.5MPa. It is estimated that these strain have advantage to strong infection strategy.
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