Nitrogen dynamics in leaves of deciduous broad-leaved tree seedlings grown in summer green forests in northern Japan
2007
Koike, T.(Hokkaido Univ., Sapporo (Japan)) | Kitaoka, S. | Masyagina, O.V. | Watanabe, Y. | Ji, D. | Maruyama, Y. | Sasa, K.
Dynamics of nitrogen in leaves of trees and seedlings of deciduous broad-leaf species were studied for improving forest management. The photosynthetic traits of canopy leaves of deciduous broad-leaved trees were measured using a canopy tower. There was a clear positive correlation between leaf nitrogen content and light saturated photosynthetic rate at sunny canopy. As reflecting the shoot development pattern, leaf senescence began from the inner part of the crown in early successional species, by contrast leaf senescence process commences from either the outer or top portion of the crown in late successional species. For regenerated seedlings in forest floor, seasonal change in the allocation pattern of leaf nitrogen coincided with the changing of light conditions through the leaf phenology of upper canopy. In light limited condition, nitrogen was allocated to chlorophyll while it allocated to more to photosynthetic carbon fixation, i.e. Rubisco in strong light condition. Nitrogen allocation was affected more by light to CO2 condition that was found in birch and beech seedlings with a FACE system.
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