A coastal and an interior Douglas fir provenance exhibit different metabolic strategies to deal with drought stress.
Drought is a major environmental stress affecting growth and vitality of forest ecosystems. In the present study, foliar nitrogen (N) and carbon (C) metabolism of two Douglas fir (Pseudotsuga menziesii) provenances with assumed different drought tolerance were investigated. We worked with 1-year-old seedlings of the interior provenance Fehr Lake (FEHR) originating from a dry environment and the coastal provenance Snoqualmie (SNO) from a more humid origin. Total C and N, structural N and the concentrations of soluble protein, total amino acids (TAAs) and individual amino acids as well as the relative abundance of polar, low-molecular-weight metabolites including antioxidants were determined in current-year needles exposed either to 42 days of drought or to 42 days drought plus 14 days of rewatering. The seedlings reacted in a provenance-specific manner to drought stress. Coastal provenance SNO showed considerably increased contents of TAAs, which were caused by increased abundance of the quantitatively most important amino acids arginine, ornithine and lysine. Additionally, the polyamine putrescine accumulated exclusively in drought-stressed trees of this provenance. In contrast, the interior provenance FEHR showed the opposite response, i.e., drastically reduced concentrations of these amino acids. However, FEHR showed considerably increased contents of pyruvate-derived and aromatic amino acids, and also higher drought-induced levels of the antioxidants ascorbate and α-tocopherol. In response to drought, both provenances produced large amounts of carbohydrates, such as glucose and fructose, most likely as osmolytes that can readily be metabolized for protection against osmotic stress. We conclude that FEHR and SNO cope with drought stress in a provenance-specific manner: the coastal provenance SNO was mainly synthesizing N-based osmolytes, a reaction not observed in the interior provenance FEHR; instead, the latter increased the levels of scavengers of reactive oxygen species. Our results underline the importance of provenance-specific reactions to abiotic stress.
Key Laboratory for Ecological Security and Protection of Sichuan Province, Mianyang Normal University, Mianxing Road West 166, 621000 Mianyang, China Chair of Tree Physiology, Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee 53, 79110 Freiburg, Germany.
Baoguo
B
Du
Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalderstr. 84, 15374 Müncheberg, Germany.
Kirstin
K
Jansen
Chair of Tree Physiology, Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee 53, 79110 Freiburg, Germany.
Anita
A
Kleiber
Chair of Tree Physiology, Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee 53, 79110 Freiburg, Germany.
Monika
M
Eiblmeier
Core Facility Metabolomics, Center for Biological Systems Analysis (ZBSA), Albert-Ludwigs-Universität Freiburg, Habsburgerstr. 49, 79104 Freiburg, Germany.
Bernd
B
Kammerer
Department of Biology, Graduate Programs in Cell and Systems Biology and Ecology and Evolutionary Biology, University of Toronto, 3359 Mississauga Road, Mississauga, ON, Canada L5L 1C6 Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg, Wonnhaldestr. 4, 79100 Freiburg, Germany.
Ingo
I
Ensminger
Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalderstr. 84, 15374 Müncheberg, Germany Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), 14195 Berlin, Germany Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), 8903 Birmensdorf, Switzerland.
Arthur
A
Gessler
Chair of Tree Physiology, Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee 53, 79110 Freiburg, Germany.
Heinz
H
Rennenberg
Chair of Tree Physiology, Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee 53, 79110 Freiburg, Germany juergen.kreuzwieser@ctp.uni-freiburg.de.
Jürgen
J
Kreuzwieser
D002244:Carbon / Q000378:metabolism*; D055864:Droughts; D017753:Ecosystem; D009584:Nitrogen / Q000378:metabolism*; D028224:Pseudotsuga / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology*; D014197:Trees / Q000378:metabolism
D017382:Reactive Oxygen Species; D002244:Carbon; D009584:Nitrogen
Pseudotsuga menziesii; amino acid; antioxidants; foliar nitrogen partitioning; osmolytes; polyamines; polyols