% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Westhoff:58851,
      author       = {Westhoff, M. and Zimmermann, D. and Schneider, H. and
                      Wegner, L.H. and Geßner, P. and Jakob, P. and Bamberg, E.
                      and Shirley, St. and Bentrup, F.-W. and Zimmermann, U.},
      title        = {{E}vidence for discontinuous water columns in the xylem
                      conduit of tall birch trees},
      journal      = {Plant biology},
      volume       = {11},
      issn         = {1435-8603},
      address      = {Oxford [u.a.] :Wiley- Blackwell},
      publisher    = {Wiley-Blackwell - STM},
      reportid     = {PreJuSER-58851},
      pages        = {307 - 327},
      year         = {2009},
      note         = {The authors are extremely grateful to the second mayor of
                      the town of Rimpar, U. Haase and to the forester W.
                      Pospichal for giving permission to fell a large number of
                      tall birches in the forest of Rimpar. We would also like to
                      thank very much our tree climbers P. Berecry and G.
                      Fleischmann for professional tree felling, sample collection
                      and rope-assisted lowering of the trees. Special thanks go
                      to our numerous helpers in the field: W. Bauer, M.
                      Behringer, A. Biegner, J. Endter, A. Gessner, F. Groeber, B.
                      Hofmann, M. Kiesel, M. Kullik, C. Low, K. Muller, S. Nieft,
                      L. Plie ss, K. Pfeffer, R. Reuss, M. Tarantola and G.
                      Zimmermann. Sincere thanks are also given to K. Schwuchow
                      and S. Nieft for excellent performance of some of the
                      microscopic investigations and to A. Liebrich, O. Reichert
                      and N. Spindler for their great help in evaluating the
                      enormous bulk of data. This work was supported by grants
                      from the BMBF to E.B. and U.Z. (0313369B).},
      abstract     = {The continuity of the xylem water columns was studied on
                      17- to 23-m tall birch trees (trunk diameter about 23 cm;
                      first branching above 10 m) all year round. Fifty-one trees
                      were felled, and 5-cm thick slices or 2-m long boles were
                      taken at regular, relatively short intervals over the entire
                      height of the trees. The filling status of the vessels was
                      determined by (i) xylem sap extraction from trunk and branch
                      pieces (using the gas bubble-based jet-discharge method and
                      centrifugation) and from trunk boles (using gravity
                      discharge); (ii) (1)H nuclear magnetic resonance imaging of
                      slice pieces; (iii) infusion experiments (dye, (86)Rb(+),
                      D(2)O) on intact trees and cut branches; and (iv) xylem
                      pressure measurements. This broad array of techniques
                      disclosed no evidence for continuous water-filled columns,
                      as postulated by the Cohesion-Tension theory, for root to
                      apex directed mass transport. Except in early spring (during
                      the xylem refilling phase) and after extremely heavy
                      rainfall during the vegetation period, cohesive/mobile water
                      was found predominantly at intermediate heights of the
                      trunks but not at the base or towards the top of the tree.
                      Similar results were obtained for branches. Furthermore,
                      upper branches generally contained more cohesive/mobile
                      water than lower branches. The results suggest that water
                      lifting occurs by short-distance (capillary, osmotic and/or
                      transpiration-bound) tension gradients as well as by
                      mobilisation of water in the parenchymatic tissues and the
                      heartwood, and by moisture uptake through lenticels.},
      keywords     = {Betula: physiology / Biological Transport: physiology /
                      Plant Roots: physiology / Plant Stems: physiology / Plant
                      Transpiration: physiology / Trees: physiology / Water:
                      physiology / Xylem: physiology / Water (NLM Chemicals) / J
                      (WoSType)},
      cin          = {ICG-3},
      ddc          = {580},
      cid          = {I:(DE-Juel1)ICG-3-20090406},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      shelfmark    = {Plant Sciences},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:19470103},
      UT           = {WOS:000265015300006},
      doi          = {10.1111/j.1438-8677.2008.00124.x},
      url          = {https://juser.fz-juelich.de/record/58851},
}