Description: Tracing cationic nutrients from xylem into stem tissue of Phaseolus vulgaris by stable isotope tracers and cryo-secondary ion mass spectrometry

This title appears in the Scientific Report : 2010

Tracing cationic nutrients from xylem into stem tissue of Phaseolus vulgaris by stable isotope tracers and cryo-secondary ion mass spectrometry

Fluxes of mineral nutrients in the xylem are strongly influenced by interactions with the surrounding stem tissues and are probably regulated by them. Toward a mechanistic understanding of these interactions, we applied stable isotope tracers of magnesium, potassium, and calcium continuously to the...

Personal Name(s):	Metzner, R.
	Schneider, H. U. / Breuer, U. / Thorpe, M.R. / Schurr, U. / Schröder, W. H.
Contributing Institute:	Phytosphäre; ICG-3 JARA-ENERGY; JARA-ENERGY
Published in:	Plant physiology, 152 (2010) S. 1030 - 1043
Imprint:	Rockville, Md.: Soc. JSTOR 2010
Physical Description:	1030 - 1043
PubMed ID:	19965970
DOI:	10.1104/pp.109.143776
Document Type:	Journal Article
Research Program:	Terrestrische Umwelt
Series Title:	Plant Physiology 152
Subject (ZB):	Biological Transport Cryoelectron Microscopy Isotopes: chemistry Microscopy, Electron, Scanning Phaseolus: chemistry Plant Stems: ultrastructure Plant Transpiration Spectrometry, Mass, Secondary Ion: methods Xylem: chemistry Isotopes J
	Publikationsportal JuSER

Please use the identifier: http://dx.doi.org/10.1104/pp.109.143776 in citations.

Fluxes of mineral nutrients in the xylem are strongly influenced by interactions with the surrounding stem tissues and are probably regulated by them. Toward a mechanistic understanding of these interactions, we applied stable isotope tracers of magnesium, potassium, and calcium continuously to the transpiration stream of cut bean (Phaseolus vulgaris) shoots to study their radial exchange at the cell and tissue level with stem tissues between pith and phloem. For isotope localization, we combined sample preparation with secondary ion mass spectrometry in a completely cryogenic workflow. After 20 min of application, tracers were readily detectable to various degrees in all tissues. The xylem parenchyma near the vessels exchanged freely with the vessels, its nutrient elements reaching a steady state of strong exchange with elements in the vessels within 20 min, mainly via apoplastic pathways. A slow exchange between vessels and cambium and phloem suggested that they are separated from the xylem, parenchyma, and pith, possibly by an apoplastic barrier to diffusion for nutrients (as for carbohydrates). There was little difference in these distributions when tracers were applied directly to intact xylem via a microcapillary, suggesting that xylem tension had little effect on radial exchange of these nutrients and that their movement was mainly diffusive.