Contrasting dynamics of water and mineral nutrients in stems shown by stable isotope tracers and cryo-SIMS

Metzner, R.; Blümler, P.; Thorpe, M.R.; Schneider, H. U.; Schröder, W. H.; Breuer, U.; Schurr, U.

doi:10.1111/j.1365-3040.2010.02157.x

Journal Article

Contrasting dynamics of water and mineral nutrients in stems shown by stable isotope tracers and cryo-SIMS

Metzner, R.FZJ* ; Thorpe, M. R.FZJ* ; Breuer, U.FZJ* ; Blümler, P.FZJ* ; Schurr, U.FZJ* ; Schneider, H. U.FZJ* ; Schröder, W. H.FZJ*

2010
Wiley-Blackwell Oxford [u.a.]

Plant, cell & environment 1393 - 1407 (2010) [10.1111/j.1365-3040.2010.02157.x]

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Please use a persistent id in citations: doi:10.1111/j.1365-3040.2010.02157.x

Abstract: 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.

Keyword(s): Isotopes: analysis (MeSH) ; Phaseolus: metabolism (MeSH) ; Phaseolus: physiology (MeSH) ; Plant Stems: metabolism (MeSH) ; Plant Stems: physiology (MeSH) ; Plant Transpiration (MeSH) ; Water: metabolism (MeSH) ; Xylem: metabolism (MeSH) ; Xylem: physiology (MeSH) ; Isotopes ; Water ; J ; calcium (auto) ; frozen-hydrated (auto) ; magnesium (auto) ; potassium (auto) ; stable isotopes (auto) ; ToF-SIMS (auto) ; transport (auto) ; xylem (auto)