| Project/Area Number |
09640745
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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 | University of Tokyo (1998-2001)
Gunma University (1997) |
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Principal Investigator |
TATENO Masaki University of Tokyo, Graduate school of Science, Associate Professor, 大学院・理学系研究科, 助教授 (00179730)
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| Project Period (FY) |
1997 – 2000
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1999: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1998: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1997: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | Carbon / Nitrogen / Vegetative growth model / Ecosystem model / Competition / Succession / N_2-fixing / Higher plants / 窒素利用 / 落葉樹 / ヤマグワ / 最大光合成速度 / 物質分配 / 窒素環境適応 / 通導性 / イタドリ / シロザ / ヤシャブシ / 窒素競争 / 窒素利用効率 / 落葉樹林 / 繁殖戦略 / ブナ / モミ / 陸上生態系 / 窒素循環 |
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| Research Abstract |
We developed a growth model of plants and a ecosystem model with special reference to carbon and nitrogen interactions. Then we tried to test the predictions of the models.
1. Optimal matter partitioning of plants depends on soul fertility, plant shape, and life history. Leaf nitrogen contents (i.e. photosynthetic capacity) predicted by the model are similar to those measured in the fields.
2. Nitrogen-fixing alder does not resorb nitrogen form senescing leaves in autumn. As a result, the alder has growth period extension in autumn. The amount of energy assimilated by the alder in the extended growth period was about six times that required for compensating the nitrogen loss. This surplus energy balance provides an advantage over the non-nitrogen-resorbing trait of nitrogen-fixing deciduous trees.
3. Our nitrogen competition model predicted that natural vegetation in the cool temperate zone must be mixed forest of deciduous trees and evergreen conifers. However, deciduous forests without the conifers are widely distributed in the zone. We measured the elongation growth of understory conifers in the deciduous forests. We showed that the saplings of conifers attain the forest canopy of the deciduous forests within 100 years from their germination. This support the model prediction. Probably, the deciduous forests in the cool temperate zone are secondary forests caused by continual fellings. About 40 year ago, Japanese people changed their energy source from trees to petroleum. Accordingly, the secondary deciduous forests are returning to natural mixed forest.
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