Application of 39K NMR spectroscopy to potassium transport in mung bean root tips

Yoshiaki Yazaki, Kazutoshi Maki, Tetsuya Sato, Eiji Ohta, Makoto Sakata

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The intracellular K+ concentration and its change in mung bean [Vigna mungo (L.) Hepper] root tips were investigated non-invasively with 39K nuclear magnetic resonance spectroscopy using a membrane impermeable shift reagent, dysprosium (III) tripolyphosphate [Dy(PPPi)7-2]. The K+ resonance was shifted to higher magnetic field in proportion to the concentration of the shift reagent. In addition to a reference capillary peak for measuring the K+ concentration, two well-resolved peaks (intra- and extracellular K+ resonances) were observed in the 39K NMR spectra of mung bean root tips. The intracellular K+ concentration was determined to be 41 mM, which was similar to the value obtained by flame photometry. When 20 mM KCl was added to the external medium, the intensity of the intracellular K+ resonance gradually increased and the net K+ uptake rate was calculated to be 4.1 micromoles per gram fresh weight per hour. After removal of KCl from the perfusion medium, the intracellular K+ concentration considerably decreased. With 31P NMR method, 2.5 mM Dy(PPPj)7-12 and 20 mM KCl had little effect on the ATP level in the cells. We have indicated that the 39K NMR method can be used to determine the K+ levels and net fluxes of the K+ transport in perfused root tips successively.

Original languageEnglish
Pages (from-to)1417-1422
Number of pages6
JournalPlant and Cell Physiology
Volume29
Issue number8
Publication statusPublished - 1988 Dec

Keywords

  • 39K NMR
  • Intracellular K+
  • Mung bean (Vigna mungo)
  • Potassium transport
  • Shift reagent

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology

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