%0 Journal Article
%A Metzner, R.
%A Thorpe, M.R.
%A Breuer, U.
%A Blümler, P.
%A Schurr, U.
%A Schneider, H. U.
%A Schröder, W. H.
%T Contrasting dynamics of water and mineral nutrients in stems shown by stable isotope tracers and cryo-SIMS
%J Plant, cell & environment
%V 33
%@ 0140-7791
%C Oxford [u.a.]
%I Wiley-Blackwell
%M PreJuSER-10545
%P 1393 - 1407
%D 2010
%Z Record converted from VDB: 12.11.2012
%X Lateral exchange of water and nutrients between xylem and surrounding tissues helps to de-couple uptake from utilization in all parts of a plant. We studied the dynamics of these exchanges, using stable isotope tracers for water (H(2)(18)O), magnesium ((26)Mg), potassium ((41)K) and calcium ((44)Ca) delivered via a cut stem for various periods to the transpiration stream of bean shoots (Phaseolus vulgaris cv. Fardenlosa Shiny). Tracers were subsequently mapped in stem cross-sections with cryo-secondary ion mass spectrometry. The water tracer equilibrated within minutes across the entire cross-section. In contrast, the nutrient tracers showed a very heterogeneous exchange between xylem vessels and the different stem tissues, even after 4 h. Dynamics of nutrients in the tissues revealed a fast and extensive exchange of nutrients in the xylem parenchyma, with, for example, calcium being completely replaced by tracer in less than 5 min. Dilution of potassium tracer during its 30 s transit in xylem sap through the stem showed that potassium concentration was up-regulated over many hours, to the extent that some of it was probably supplied by phloem recirculation from the shoot.
%K Isotopes: analysis
%K Phaseolus: metabolism
%K Phaseolus: physiology
%K Plant Stems: metabolism
%K Plant Stems: physiology
%K Plant Transpiration
%K Water: metabolism
%K Xylem: metabolism
%K Xylem: physiology
%K Isotopes (NLM Chemicals)
%K Water (NLM Chemicals)
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:20444220
%U <Go to ISI:>//WOS:000279610200014
%R 10.1111/j.1365-3040.2010.02157.x
%U https://juser.fz-juelich.de/record/10545