title: Contrasting carbon allocation responses of juvenile European beech (Fagus sylvatica) and Norway spruce (Picea abies) to competition and ozone.
abstract: Allocation of recent photoassimilates of juvenile beech and spruce in response to twice-ambient ozone (2 × O(3)) and plant competition (i.e. intra vs. inter-specific) was examined in a phytotron study. To this end, we employed continuous (13)CO(2)/(12)CO(2) labeling during late summer and pursued tracer kinetics in CO(2) released from stems. In beech, allocation of recent photoassimilates to stems was significantly lowered under 2 × O(3) and increased in spruce when grown in mixed culture. As total tree biomass was not yet affected by the treatments, C allocation reflected incipient tree responses providing the mechanistic basis for biomass partitioning as observed in longer experiments. Compartmental modeling characterized functional properties of substrate pools supplying respiratory C demand. Respiration of spruce appeared to be exclusively supplied by recent photoassimilates. In beech, older C, putatively located in stem parenchyma cells, was a major source of respiratory substrate, reflecting the fundamental anatomical disparity between angiosperm beech and gymnosperm spruce.
authors.affiliation: Ecophysiology of Plants, Department of Ecology and Ecosystem Management, Technische Universität München, Von-Carlowitz-Platz 2, 85354 Freising, Germany.
authors.forename: Wilma
authors.initials: W
authors.lastname: Ritter
authors.affiliation: Lehrstuhl für Grünlandlehre, Department of Plant Sciences, Technische Universität München, Alte Akademie 12, 85350 Freising, Germany; Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Christoph Andreas
authors.initials: CA
authors.lastname: Lehmeier
authors.affiliation: Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Biochemical Plant Pathology, Department of Environmental Engineering, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
authors.forename: Jana Barbro
authors.initials: JB
authors.lastname: Winkler
authors.affiliation: Ecophysiology of Plants, Department of Ecology and Ecosystem Management, Technische Universität München, Von-Carlowitz-Platz 2, 85354 Freising, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Matyssek
authors.affiliation: Ecophysiology of Plants, Department of Ecology and Ecosystem Management, Technische Universität München, Von-Carlowitz-Platz 2, 85354 Freising, Germany. Electronic address: grams@tum.de.
authors.forename: Thorsten Erhard
authors.initials: TE
authors.lastname: Edgar Grams
mesh_terms: D028202:Abies; D000393:Air Pollutants / Q000633:toxicity*; D018533:Biomass; D002244:Carbon / Q000378:metabolism*; D019069:Cell Respiration; D029964:Fagus / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D009664:Norway; D010126:Ozone / Q000633:toxicity*; D028222:Picea / Q000187:drug effects / Q000502:physiology*; D028223:Pinus; D012621:Seasons; D014197:Trees / Q000502:physiology
chemical_list: D000393:Air Pollutants; D010126:Ozone; D002244:Carbon
keywords: CO(2) efflux; Compartmental modeling; Plant–plant competition (intra versus inter-specific); Stable carbon isotope ((13)CO(2)/(12)CO(2)) labeling; Tropospheric ozone (O(3))