open access

https://hdl.handle.net/2115/70488

変動環境における北日本の落葉広葉樹の葉成分と防御特性に関する生理的・化学量論的研究 [全文の要約]

英語

2017-09-25

Hokkaido University

https://www.lib.hokudai.ac.jp/dissertations/copy-guides/

In chapter 1, I made a general introduction about environmental changes, tree species as well as general description about nutrients stoichiometry and defense characteristics. In natural forests, uptake and release are two important factors due to representative of primary flux in ecosystem. Nutrients are absorbed from soil and being used for plants growth, physiological responses or being returned via decomposition through litter fall and being available again for next nutrient cycling. Consequently, stoichiometry is dependent on the balance among uptake, amount of retranslocation rate and loss of the processes. At the same time, plant defense is a vital mechanism for biological conservation and improvement of which is essential on forest maintenance and biological diversification. Global environment has been dramatically changing due to human activities, especially elevated atmospheric carbon dioxide (CO2), ozone (O3), and nitrogen (N) as a precursor for O3. Atmospheric CO2 has been globally increasing and promotes plant growth via photosynthetic enhancement for an extent. At the same time, ground-level O3 has also been continuously increasing especially in Asia. Elevated O3 can accelerate foliar senescence and negatively affect the vigor and health of forests. Moreover, soil conditions (e.g. nutrient availability) also affect the physiological function of both nutrient retranslocation and plant defense. As representatives of deciduous broad-leaved tree species native to northern Japan, Japanese white birch (Bp: Betula platyphylla var. japonica Hara), Siebold’s beech (Fc: Fagus crenata Blume), Mizunara oak (Qm: Quercus mongolica Fisch. ex Ledeb. var. crispula (Blume) Ohashi) and Konara oak (Qs: Quercus serrata Murray) are applied to this study. Specific O3 sensitivity has been estimated in sequence of beech, birch and oak, with determinate, indeterminate and semi-determinate shoot growth pattern, respectively. To assess the responses of the above species on various environmental changes, three researches which divided into 4 chapters have been carried out with a free-air enrichment system to simulate forest ecosystems.

甲第12882号

博士(農学)

(主査) 特任教授 小池 孝良, 教授 波多野 隆介, 准教授 渡部 敏裕, 准教授 中村 誠宏 （北方生物圏フィールド科学センター）, 教授 Grantz A. David (カリフォルニア大学リバーサイド校)

農学院（環境資源学専攻）

博士論文

Version of Record