title: Below-ground carbon allocation in mature beech and spruce trees  following  long-term, experimentally enhanced O3 exposure in Southern Germany.
abstract: Canopies of adult European beech (Fagus sylvatica) and Norway spruce (Picea abies) were labeled with CO(2) depleted in (13)C to evaluate carbon allocation belowground. One-half the trees were exposed to elevated O(3) for 6 yrs prior to and during the experiment. Soil-gas sampling wells were placed at 8 and 15 cm and soil CO(2) was sampled during labeling in mid-late August, 2006. In beech, delta(13)CO(2) at both depths decreased approximately 50 h after labeling, reflecting rapid translocation of fixed C to roots and release through respiration. In spruce, label was detected in fine-root tissue, but there was no evidence of label in delta(13)CO(2). The results show that C fixed in the canopy rapidly reaches respiratory pools in beech roots, and suggest that spruce may allocate very little of recently-fixed carbon into root respiration during late summer. A change in carbon allocation belowground due to long-term O(3) exposure was not observed.
authors.affiliation: US Environmental Protection Agency, Western Ecology Division, 200 SW 35th St., Corvallis, OR 97333, United States. Andersen.christian@epa.gov
authors.forename: Christian P
authors.initials: CP
authors.lastname: Andersen
authors.forename: Wilma
authors.initials: W
authors.lastname: Ritter
authors.forename: Jillian
authors.initials: J
authors.lastname: Gregg
authors.forename: Rainer
authors.initials: R
authors.lastname: Matyssek
authors.forename: Thorsten E E
authors.initials: TE
authors.lastname: Grams
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D002244:Carbon / Q000032:analysis*; D002247:Carbon Isotopes; D029964:Fagus / Q000187:drug effects / Q000378:metabolism*; D005858:Germany; D007553:Isotope Labeling; D010126:Ozone / Q000633:toxicity*; D028222:Picea / Q000187:drug effects / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D002247:Carbon Isotopes; D010126:Ozone; D002244:Carbon