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@PHDTHESIS{Fllner:46950,
      author       = {Füllner, Kerstin},
      title        = {{T}he influence of spatially heterogeneous soil
                      temperatures on plant structure and function},
      volume       = {76},
      school       = {Universität Düsseldorf},
      type         = {Dr. (Univ.)},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {PreJuSER-46950},
      isbn         = {978-3-89336-507-4},
      series       = {Schriften des Forschungszentrums Jülich. Reihe Umwelt /
                      Environment},
      pages        = {124 S.},
      year         = {2007},
      note         = {Record converted from VDB: 12.11.2012; Universität
                      Düsseldorf, Diss., 2007},
      abstract     = {In nature, vertical gradients in soil temperature are
                      ubiquitous, but research on the influence of spatially
                      heterogeneous soil temperatures on plant structure and
                      function is scarce. Most experiments with plants even ignore
                      the gradient in soil temperature found under natural
                      conditions. For this reason, in this study it was examined
                      for the first time, whether a vertical gradient in soil
                      temperature influences plant growth and development in a
                      different way than uniform root temperatures usually
                      examined in the literature. Furthermore, it was analyzed
                      whether functional and/or structural traits of the plant
                      might be responsible for these potential effects. Data of
                      barley plants ($\textit{Hordeum vulgare}$ cv. Barke) grown
                      at a vertical root temperature gradient (RTG) of 20-10°C
                      from the top to the bottom of a plant pot were compared with
                      data obtained for barley plants grown at uniform root
                      temperatures (RT) of 10°C, 15°C and 20°C, respectively.
                      Plants grown at the RTG developed faster and produced more
                      biomass compared to plants grown at uniform root
                      temperatures. The root system was characterized by shallow
                      rooting with most roots present in 0-10 cm depth and a quite
                      high fraction of thick roots ($\geq$ 1.0 mm in diameter) in
                      the entire root system. In this way, the root system of
                      plants grown at the RTG was similar to plants grown at 15°C
                      RT. However in contrast to 15°C RT, plants grown at
                      20-10°C RTG did not reach highest fraction of total root
                      length in 0-5 cm but in 5-10 cm depth, although less root
                      dry weight was present in 5-10 cm compared to 0-5 cm depth
                      at both temperature treatments. This was explained by
                      differences in fractions of individual root diameters within
                      the respective depths. Additionally, experiments on N
                      metabolism in plants revealed higher concentrations of most
                      free amino acids in shoots at 20-10°C RTG and varying
                      protein concentrations in roots between plants grown at RTG
                      and 15°C uniform root temperature. Therefore, it was
                      demonstrated that a vertical gradient in root temperature
                      influences plant structure and function in a different way
                      than the respective uniform root temperature representing
                      the average temperature of this gradient. No significant
                      differences between 20-10°C RTG and 15°C RT occurred, when
                      nutrient uptake and translocation were analyzed with stable
                      isotopes as tracers ($^{15}$N, $^{25}$Mg). However, in
                      general it has to be stated that at active nutrient uptake
                      processes direct root temperature effects, e.g. lower N
                      uptake at 10°C RT compared to higher root temperatures were
                      overridden by the adaptation of plant structure to the
                      respective root temperature. This underlines the importance
                      of structural traits (e.g. biomass allocation to the shoot,
                      fractions of individual root diameters) to nutrient demand
                      and supply. In contrast, direct temperature effects remained
                      detectable at passive uptake processes (e.g. Mg). Therefore,
                      it was hypothesized, that plants grown at a vertical root
                      temperature gradient grow faster compared to plants at
                      uniform root temperatures due to a combination of structural
                      and functional components making nutrient uptake,
                      translocation and use more effective. Furthermore, it was
                      shown, that root temperature effects on plant structure
                      change in amplitude with plant age and development stage.
                      Consequently, effects found in this study represent a
                      snapshot of plant responses to root temperature.},
      cin          = {ICG-3},
      ddc          = {333.7},
      cid          = {I:(DE-Juel1)ICG-3-20090406},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/46950},
}