A species' response to increased temperature depends on its thermal optimum for photosynthesis and growth, and its current operation either at or below the optimum. In Douglas-fir, the 2003 drought and heat wave showed diverging effects on radial growth ranging from no response at moist sites to significant decreases at dry sites in Germany and Switzerland. Ĭompared to deciduous tree species, evergreen species show a weak growth increase or no growth response to constant, yet, moderate temperature increases. periods of increased temperature in concert with drought – on the physiology of trees are not well understood, e.g. Our insights into the adaptation and acclimation potential of tree species towards climatic change are still incomplete and especially the effects of heat waves i.e. Tree growth and physiological performance will depend on both the acclimation to increased temperatures and the resistance against extreme events such as the hot-dry summer 2003 in Central Europe. In addition to a continuous increase in air temperature, the frequency of climate extremes, including heat waves, has been predicted to strongly increase, –. The projected increase in air temperature is the most direct and best predictable effect of increasing tropospheric CO 2 concentrations.
Global climate change is expected to affect forest growth and productivity. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. All relevant data are within the paper and its Supporting Information files.įunding: The authors acknowledge financial support by the Deutsche Forschungsgemeinschaft (DFG) under contract numbers GE1090/7-1 to AG, KR 2010/4-1 to JK, and EN829/5-1 to IE. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: The authors confirm that all data underlying the findings are fully available without restriction. Received: AugAccepted: NovemPublished: December 1, 2014Ĭopyright: © 2014 Jansen et al.
PLoS ONE 9(12):Įditor: Wei Wang, Henan Agricultural Univerisity, China (2014) Douglas-Fir Seedlings Exhibit Metabolic Responses to Increased Temperature and Atmospheric Drought. Douglas-fir might be a potentially important tree species for forestry in Central Europe under changing climatic conditions.Ĭitation: Jansen K, Du B, Kayler Z, Siegwolf R, Ensminger I, Rennenberg H, et al. elevated temperatures and atmospheric drought). We conclude that metabolic acclimation successfully contributes to maintain functioning and physiological activity in seedlings of both Douglas-fir provenances under conditions that are expected during heat waves (i.e. The metabolite profile revealed that the simulated heat wave induced a switch in stress protecting compounds from proline to polyols. Plant biomass was only slightly affected by increased temperatures and atmospheric drought but the more negative apparent respiratory fractionation indicated a temperature-dependent decrease in the commitment of substrate to the tricarboxylic acid cycle. We analysed (i) plant biomass, (ii) carbon stable isotope composition as an indicator for time integrated intrinsic water use efficiency, (iii) apparent respiratory carbon isotope fractionation as well as (iv) the profile of polar low molecular metabolites. In this study, we identified the physiological and growth responses of seedlings from two different Douglas-fir provenances to increased temperature and atmospheric drought during a period of 92 days. However, Douglas-fir is often discussed as an alternative for the drought and heat sensitive Norway spruce, because some provenances are considered to be well adapted to drier and warmer conditions. Norway spruce might be at risk in the future climate of Central Europe. In the future, periods of strongly increased temperature in concert with drought (heat waves) will have potentially detrimental effects on trees and forests in Central Europe.
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