title: Photosynthetic traits of Siebold's beech and oak saplings grown under free air ozone exposure in northern Japan.
abstract: We set up a free-air ozone (O(3)) exposure system for determining the photosynthetic responses of Siebold's beech (Fagus crenata) and oak (Quercus mongolica var. crispula) to O(3) under field conditions. Ten-year-old saplings of beech and oak were exposed to an elevated O(3) concentration (60 nmol mol(-1)) during daytime from 6 August to 11 November 2011. Ozone significantly reduced the net photosynthetic rate in leaves of both species in October, by 46% for beech and 15% for oak. In beech there were significant decreases in maximum rate of carboxylation, maximum rate of electron transport in photosynthesis, nitrogen content and photosynthetic nitrogen use efficiency, but not in oak. Stomatal limitation of photosynthesis was unaffected by O(3). We therefore concluded photosynthesis in beech is more sensitive to O(3) than that in oak, and the O(3)-induced reduction of photosynthetic activity in beech was due not to stomatal closure, but to biochemical limitation.
authors.affiliation: Silviculture and Forest Ecological Studies, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Watanabe
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Hoshika
authors.forename: Naoki
authors.initials: N
authors.lastname: Inada
authors.forename: Xiaona
authors.initials: X
authors.lastname: Wang
authors.forename: Qiaozhi
authors.initials: Q
authors.lastname: Mao
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Koike
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D004579:Electron Transport; D029964:Fagus / Q000187:drug effects* / Q000502:physiology; D007564:Japan; D009584:Nitrogen / Q000378:metabolism; D010126:Ozone / Q000633:toxicity*; D010788:Photosynthesis / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects; D029963:Quercus / Q000187:drug effects* / Q000502:physiology
chemical_list: D000393:Air Pollutants; D010126:Ozone; D009584:Nitrogen