| Project/Area Number |
09660173
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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 |
林産学
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
FUJIKAWA Seizo The Institute of Low Temperature Science, Hokkaido Univ.Asso.Prof., 低温科学研究所, 助教授 (50091492)
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| Co-Investigator(Kenkyū-buntansha) |
SANO Yuzou Fac.Agr., Hokkaido Univ.Lec., 農学部, 助手 (90226043)
OHTANI Jun Fac.Agr., Hokkaido Univ.Prof., 農学部, 教授 (30001465)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1998: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Cell wall / Cryo-scanning electron microscope / Freezing to lerance / Cold acclimation / Xylem ray parenchyma cell / Supercooling / Extracellular freezing / Cold climate / 細胞壁 / 凍結挙動 / 深過冷却 |
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| Research Abstract |
Present research clarified important role of cell wall properties in the adaptation of xylem ray parenchyma cells to subzero temperatures. First, we showed that macroscopic structural differences in the cell walls affected distinctly to the freezing behavior by examing freezing behavior of xylem ray parenchyma cells of softwood species with observation by cryo-scanning electron microscopy. It was shown that xylem ray parenchyma cells constructed of unlignified thin cell walls with soft appearance (Sciadopitys verticillata, Pinus densiflora, P.parifilora) responded to freezing by extracellular freezing, while xylem ray parenchyma cells constructed of lignified thick cell walls with rigid appearance (Cryptomeria japoriica, Larix leptolepis) responded to freezing by deep supercooling. Second, we showed that microscpic structural differences in the cell walls, which were not detected by observation with electron microscopy, also affected to the freezing behavior in xylem ray parenchyma cells constructed of thick cell walls with rigid appearance. For example, xylem ray parenchyma cells of birch responded to freezing by supercooling in summer but they responded to freezing by extracellular freezing in winter, although no seasonal alteration of cell wall structures was detected by electron microscope observations. For clarifying the mechanisms of seasonal alteration of cell wall properties upon freezing behavior, we examined seasonal change of the cell wall-binding proteins and found distinct accumulation of Lowtemperature-Induced Apoplastic Proteins LIAP29, 28 and 23. We are currently continuing the biochemical analysis of these proteins.
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