Photosynthetic responses to ozone of upper and lower canopy leaves of Fagus crenata Blume seedlings grown under different soil nutrient conditions.
We aimed to clarify the effects of ozone (O3) on photosynthetic ability of upper and lower canopy leaves of Fagus crenata Blume seedlings grown under different soil nutrient conditions. To accomplish this objective, we analyzed the response of photosynthetic parameters such as maximum carboxylation rate (Vcmax) to cumulative stomatal O3uptake (ΣFst) and reduction rate of Vcmaxper unit ΣFstas an index of detoxification capacity for O3. The seedlings of Fagus crenata were grown for two growing seasons (2014-2015) in nine treatments comprised of a combination of three levels of gas treatments (charcoal-filtered air or 1.0- or 1.5-times ambient O3concentration) and three levels of soil nutrient treatments (non-fertilized or a supply of relatively low or high concentrations of compound fertilizer). The nutrient supply significantly increased the degree of O3-induced reduction in Vcmaxin September. However, nutrient supply did not significantly increase ΣFstand reduce the detoxification capacity for O3. On the other hand, the degree of O3-induced reduction in Vcmaxof upper canopy leaves was higher as compared with that of lower canopy leaves in August due to the higher ΣFst. However, the reduction rate of Vcmaxper unit ΣFstin lower canopy leaves was higher than that in upper canopy leaves, indicating lower detoxification capacity for O3in lower canopy leaves. Reduction rate of Vcmaxper unit ΣFstover the threshold, which is assumed to be proportional to gross photosynthetic rate, was similar between upper and lower canopy leaves. Therefore, capacity of photosynthetic CO2assimilation is likely to be associated with detoxification capacity for O3in upper and lower canopy leaves of F. crenata seedlings grown under different soil nutrient conditions.
United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
Yoshiyuki
Y
Kinose
Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
Yoshinobu
Y
Fukamachi
Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
Shigeaki
S
Okabe
Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
Hiroka
H
Hiroshima
Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
Makoto
M
Watanabe
Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan. Electronic address: izuta@cc.tuat.ac.jp.
Takeshi
T
Izuta
D000064:Acclimatization / Q000502:physiology; D019069:Cell Respiration; D029964:Fagus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D007564:Japan; D010126:Ozone / Q000378:metabolism* / Q000494:pharmacology; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D012621:Seasons; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D012987:Soil / Q000737:chemistry*
D012987:Soil; D010126:Ozone
Canopy leaf position; Detoxification capacity; Fagus crenata Blume; Soil nutrient conditions; Stomatal ozone uptake