title: Light compensation points in shade-grown seedlings of deciduous broadleaf tree species with different successional traits raised under elevated CO2.
abstract: We measured leaf photosynthetic traits in shade-grown seedlings of four tree species native to northern Japan, raised under an elevated CO2 condition, to investigate the effects of elevated CO2 on shade tolerance of deciduous broadleaf tree species with different successional traits. We considered Betula platyphylla var. japonica and Betula maximowicziana as pioneer species, Quercus mongolica var. crispula as a mid-successional species, and Acer mono as a climax species. The plants were grown under shade conditions (10% of full sunlight) in a CO2 -regulated phytotron. Light compensation points (LCPs) decreased in all tree species when grown under elevated CO2 (720 μmol·mol(-1) ), which were accompanied by higher apparent quantum yields but no photosynthetic down-regulation. LCPs in Q. mongolica and A. mono grown under elevated CO2 were lower than those in the two pioneer birch species. The LCP in Q. mongolica seedlings was not different from that of A. mono in each CO2 treatment. However, lower dark respiration rates were observed in A. mono than in Q. mongolica, suggesting higher shade tolerance in A. mono as a climax species in relation to carbon loss at night. Thus, elevated CO2 may have enhanced shade tolerance by lowering LCPs in all species, but the ranking of shade tolerance related to successional traits did not change among species under elevated CO2 , i.e. the highest shade tolerance was observed in the climax species (A. mono), followed by a gap-dependent species (Q. mongolica), while lower shade tolerance was observed in the pioneer species (B. platyphylla and B. maximowicziana).
authors.affiliation: Department of Plant Ecology, Forestry and Forest Products Research Institute, Tsukuba, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kitao
authors.affiliation: Department of Forest Science, Hokkaido University, Sapporo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hida
authors.affiliation: Department of Forest Science, Hokkaido University, Sapporo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Eguchi
authors.affiliation: Department of Plant Ecology, Forestry and Forest Products Research Institute, Tsukuba, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tobita
authors.affiliation: Department of Plant Ecology, Forestry and Forest Products Research Institute, Tsukuba, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Utsugi
authors.affiliation: Hokkaido Research Center, Forestry and Forest Products Research Institute, Sapporo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Uemura
authors.affiliation: Department of Plant Ecology, Forestry and Forest Products Research Institute, Tsukuba, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kitaoka
authors.affiliation: Department of Forest Science, Hokkaido University, Sapporo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Koike
mesh_terms: D000064:Acclimatization; D031002:Acer / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D029662:Betula / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000494:pharmacology*; D007564:Japan; D010641:Phenotype; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects*; D018515:Plant Leaves / Q000502:physiology / Q000528:radiation effects; D029963:Quercus / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D036226:Seedlings / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D013472:Sunlight; D014197:Trees
chemical_list: D002245:Carbon Dioxide; D002244:Carbon
keywords: Apparent quantum yield; CO2 enrichment; dark respiration; photosynthesis; shade tolerance