Cong Shi1, Fankang Meng1,2, Toshihiro Watanabe1, Fuyuki Satoh3, Takayoshi Koike1*
Graduate School of Agriculture, Hokkaido University, Sapporo 060-8689, Japan
- College of Life Science, Nankai University, Tianjin 300071, China
- Hokkaido University Forests, Sapporo 060-0809, Japan
*Corresponding author: Takayoshi Koike: [email protected]
To clarify effects of ozone (O3) on foliar nitrogen (N) contents dynamics in three representative woody plant seedlings: birch (Betula platyphylla var. japonica), oak (Quercus mongolica var. crispula), and beech (Fagus crenata) grown in elevated O3 (eO3), we investigated N contents in live and senescing leaves, the relation of N content differences and leaf mass per area (LMA) of each species. The 3 species seedlings were planted in a free-air O3 enrichment system for one growing season with 3 replicated plots exposed to the air or O3 at about 2.5 times the ambient. In our study, about 60 % of foliar N was retranslocated under eO3 conditions in birch; nearly 70 % of N in live leaves of oak was decreased by O3; and negative correlations were found between LMA and N at ambient. Based on the results, we discussed plausible understanding physiologically and biochemically to conclude that foliar N contents of birch is more sensitive than beech in response to O3, especially for the senescing leaves; on the other hand, LMA may be considered as an index parameter in speculation of the changes in foliar N contents at ambient O3 concentrations.