title: Effects of high atmospheric CO2 concentration on root hydraulic conductivity of conifers depend on species identity and inorganic nitrogen source.
abstract: We examined root hydraulic conductivity (L(p)) responses of one-year-old seedlings of four conifers to the combined effects of elevated CO2 and inorganic nitrogen (N) sources. We found marked interspecific differences in L(p) responses to high CO2 ranging from a 37% increase in P. abies to a 27% decrease in P. menziesii, but these effects depended on N source. The results indicate that CO2 effects on root water transport may be coupled to leaf area responses under nitrate (NO(3)(-)), but not ammonium (NH(4)(+)) dominated soils. To our knowledge, this is the first study that highlights the role of inorganic N source and species identity as critical factors that determine plant hydraulic responses to rising atmospheric CO2 levels. The results have important implications for understanding root biology in a changing climate and for models designed to predict feedbacks between rising atmospheric CO2, N deposition, and ecohydrology.
authors: Department of Biological Sciences, University of Illinois at Chicago, 840 West Taylor Street, Chicago, IL 60607, United States.
authors: Tobias
authors: T
authors: Gebauer
authors: Hormoz
authors: H
authors: Bassirirad
mesh_terms: D028202:Abies / Q000737:chemistry / Q000378:metabolism*; D000393:Air Pollutants / Q000032:analysis*; D001692:Biological Transport; D002245:Carbon Dioxide / Q000032:analysis*; D006874:Hydrostatic Pressure; D007700:Kinetics; D009566:Nitrates / Q000378:metabolism*; D028222:Picea / Q000737:chemistry / Q000378:metabolism*; D018517:Plant Roots / Q000737:chemistry* / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D014867:Water / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D014867:Water; D002245:Carbon Dioxide