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Leaf‐level nitrogen‐use efficiency of canopy and understorey species in a beech forest
Author(s) -
Yasumura Y.,
Hikosaka K.,
Matsui K.,
Hirose T.
Publication year - 2002
Publication title -
functional ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 154
eISSN - 1365-2435
pISSN - 0269-8463
DOI - 10.1046/j.1365-2435.2002.00691.x
Subject(s) - canopy , beech , understory , biology , botany , nitrogen , biomass (ecology) , sasa , agronomy , horticulture , physics , quantum mechanics
Summary1 In a forest stand, canopy and understorey species grow at completely different irradiances and consequently with different carbon and nitrogen availability ratios. We studied how the difference in growth irradiance influenced plant N use in a mature beech forest. 2 We defined leaf‐level nitrogen‐use efficiency (NUE L ) as the amount of the leaf dry mass produced per unit N taken up by leaves. NUE L was similar between the canopy species ( Fagus crenata ) and the understorey species ( Lindera umbellata and Magnolia salicifolia ). 3 NUE L was analysed further as the product of two components: leaf‐level N productivity (NP L ) and mean residence time of leaf N (MRT L ). The canopy species had significantly larger NP L and significantly shorter MRT L than the understorey species. 4 As the photosynthetic capacity was similar among the species, different NP L between the species was attributable largely to the difference in light conditions to which their leaves were exposed. 5 The difference in MRT L was not attributable to potential efficiency of N resorption ( R EFF ) determined at leaf senescence, but to actual R EFF , which depended on the amount of green leaf lost before full senescence. The canopy species had significantly smaller actual R EFF because of strong wind actions in the canopy. 6 Although the canopy species realized higher NP L by virtue of high irradiance, it had shorter MRT L due to wind damage to pre‐senescent leaves. On the other hand, the canopy species had shorter NP L under shady conditions, but had longer MRT L with little wind damage. Interplay of local environmental factors such as light and wind strongly influenced N use by plants in the beech forest.