Growth and Nitrogen Availability of Red Pine Seedlings under High Nitrogen Load and Elevated Ozone |
| |
Authors: | Tatsuro Nakaji Takuya Kobayashi Mihoko Kuroha Kumiko Omori Yuko Matsumoto Tetsushi Yonekura Katsuhiko Watanabe Jarkko Utriainen Takeshi Izuta |
| |
Institution: | 1. Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, Ibaraki, 305–8506, Japan 2. Central Research Institute of Electric Power Industry, Abiko, Chiba, 270–1194, Japan 3. Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183–8509, Japan
|
| |
Abstract: | To evaluate the effect of increasing nitrogen (N) deposition and tropospheric ozone (O3) concentrations on N-saturated forest ecosystems, we investigated the response of Japanese red pine (Pinus densiflora), an N-saturation sensitive tree species, to increasing N load under elevated O3 concentrations. One-year-old seedlings of red pine were treated with three levels of N supply (0, 50 and 100 mg N L-1 fresh soil volume) under two levels of atmospheric O3 concentration (< 5 and 60 ppb) for two growing seasons. Nitrogen treatment did not stimulate dry matter production of the seedlings. Growth inhibition was observed in the highest N treatment under low O3 and in the two higher N treatments under elevated O3. Irrespective of the O3 concentration, increasing N supply negatively affected root growth and mycorrhizal development in fine roots, resulting in a reduction in P and Mg uptake from the soil. Net photosynthetic rate was significantly reduced by both the highest N treatment under low O3 and the two higher N treatments under elevated O3, together with decreased N-availability to Rubisco. Nitrogen assimilated from NO3 - to amino acid in the needles was not affected by the treatments. However, needle protein concentration was reduced by the highest N-treatment under low O3 and by the two higher N-treatments under elevated O3. These results suggest that elevated O3 potentially disturbs the N-availability in the form of protein including Rubisco, and may advance the negative effects of excessive N-deposition on N-sensitive plant species in N-saturated forests. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|