Effect of potassium deficiency on the plasma membrane H+-ATPASE of the wood ray parenchyma in poplar

M. Arend, G. Monshausen, C. Wind, M. H. Weisenseel, J. Fromm

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23 Scopus citations


The effect of K+ deficiency on the plasma membrane (PM) H +-ATPase was studied in young stems of poplar plants (Populus tremula x tremuloides) grown with low or full-strength K+ supply. Immunological assays using different antibodies were applied to test if K + deficiency affects the amount of immunodetectable PM H +-ATPases in the stem tissue. The monoclonal antibody clone 46 E5 B11 revealed an increased abundance of PM H+-ATPases under conditions of low K+ supply, and immunolabelling experiments showed that this increase was restricted to vessel-associated cells (VACs) of the wood ray parenchyma. Replacement of the monoclonal antibody by a polyclonal antibody against PM H+-ATPase gave a specific immunoreactivity on blots as well as tissue sections too, but the labeling intensity showed no difference between plants with low or full-strength K+ supply. Measurements of extracellular H+ concentrations using non-invasive, H +-selective microelectrodes revealed a lowering of the pH at the surface of VACs and an enhancement of net efflux of H+ in plants grown with low K+ supply. The present results indicate an up-regulation of specific isoforms of the PM H+-ATPase in VACs under K+-deficient conditions and suggest a key role for these PM H +-ATPases in unloading K+ from the xylem stream.

Original languageEnglish (US)
Pages (from-to)1288-1296
Number of pages9
JournalPlant, Cell and Environment
Issue number10
StatePublished - Oct 1 2004

All Science Journal Classification (ASJC) codes

  • Physiology
  • Plant Science


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