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| Koyama, Kohei; Kikuzawa, Kihachiro. |
| Light absorption and use efficiency (LAUE mol mol−1, daily gross photosynthesis per daily incident light) of each leaf depends on several factors, including the degree of light saturation. It is often discussed that upper canopy leaves exposed to direct sunlight are fully light-saturated. However, we found that upper leaves of three temperate species, a heliophytic perennial herb Helianthus tuberosus, a pioneer tree Alnus japonica, and a late-successional tree Fagus crenata, were not fully light-saturated even under full sunlight. Geometrical analysis of the photosynthetic light response curves revealed that all the curves of the leaves from different canopy positions, as well as from the different species, can be considered as different parts of a single... |
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Palavras-chave: Scaling; Big leaf model; Helianthus tuberosus; Alnus japonica; Fagus crenata. |
| Ano: 2010 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4482 |
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| Koyama, Kohei; Kikuzawa, Kihachiro. |
| We investigated the leaf demography of a temperate woody liana, Akebia trifoliata, in a temperate forest in Japan, Akebia is semi-evergreen: some leaves are shed before winter, while others remain through the winter. Previous studies of semi-evergreen species found that variation in leaf life span was caused by variation in the timing of leaf emergence, Leaves that appeared just before winter over-wintered, while leaves appearing earlier were shed, However, it is unclear whether leaves of the same cohort (i.e., leaves that appear at the same time within a single site) show variation in life span under the effect of strong seasonality. To separate variation in life span among the leaves in each cohort from variation among cohorts, we propose a new method -... |
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Palavras-chave: Akebia trifoliata; Leaf demography; Leaf lifespan; Leaf phenology; Liana; Phenotypic plasticity; Semi-evergreen. |
| Ano: 2016 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4523 |
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| Koyama, Kohei; Kikuzawa, Kihachiro. |
| It has been well established that leaf longevity is linked to the carbon economy of plants. We used this relationship to predict leaf lifetime carbon gains from leaf lifespan, and estimated the gross primary production (GPP) of a young deciduous forest of Japanese beech (Fagus crenata) located in central Japan. The light-saturated photosynthetic rates of the leaves were measured repeatedly during the growing season. We used the leaf lifespan to calculate the conversion coefficient from the light-saturated photosynthetic rate into the realized leaf lifetime carbon gain under field conditions. The leaf turnover rate was estimated using litter traps. GPP was estimated as the product of lifetime carbon gain per unit of leaf mass, and the annual leaf turnover... |
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Palavras-chave: Fagus crenata; Functional leaf longevity; Gross primary production; Mean labor time; Temperate forest. |
| Ano: 2016 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4524 |
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