| Project/Area Number |
09640760
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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 |
生態
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| Research Institution | National Institute of Polar Research |
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Principal Investigator |
IMURA Satoshi (1998-1999) National Institute of Polar Research, Research Associate, 研究系, 助手 (90221788)
工藤 栄 (1997) 国立極地研究所, 北極圏環境研究センター, 助手 (40221931)
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| Co-Investigator(Kenkyū-buntansha) |
KASHINO Yasuhiro Himeji Institute of Technology, Faculty of Science, Research Associate, 理学部, 助手 (20221872)
伊村 智 国立極地研究所, 研究系, 助手 (90221788)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Ice algae / Diatom / Photosynthesis / Photosystem / RubisCO / Diadinoxan thin cycle / Acclimation / accessory pigments / Rubis CO / クロロフィルa / 光捕集色素系 / 蛍光 / アイスアルジ- / 光合成補助色素 / 光環境応答 |
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| Research Abstract |
Ice algae and diatoms perform highly efficient photosynthesis, in spite of these very severe environments. We investigated how their light-harvesting systems or photosystems acclimate to very low irradiance to achieve efficient photosynthesis. The way of acclimation was very unique, which was opposite to that of higher plants or green algae. In ice algae, the accessory pigments and also RubisCO were decreased and the ratio of photosystem I (PSI) to PS II was lowered in lower irradiance. And photosynthetic systems acclimated highly to very low irradiance were protected by functional diadinoxanthin cycle, equivalent to the xanthophylls cycle of higher plant, against higher irradiance.
The maximum photosysthetic rate was also retained at the same level and photo inhibition could not be observed under illumination up to -800 uEm-2s-1. These properties may indicate that the efficient light-energy utilization and functioning of photosystems of the diatom cells under large variation of irradiance at short time-scale relative to their generation time such as in the ice.
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