Electrophysiological characterization of pathways for K+ uptake into growing and non-growing leaf cells of barley

A - Papers appearing in refereed journals

Volkow, V., Boscari, A., Clement, M., Miller, A. J., Amtmann, A. and Fricke, W. 2009. Electrophysiological characterization of pathways for K+ uptake into growing and non-growing leaf cells of barley. Plant, Cell and Environment. 32 (12), pp. 1778-1790.

AuthorsVolkow, V., Boscari, A., Clement, M., Miller, A. J., Amtmann, A. and Fricke, W.
Abstract

Potassium is a major osmolyte used by plant cells. The accumulation rates of K+ in cells may limit the rate of expansion. In the present study, we investigated the involvement of ion channels in K+ uptake using patch clamp technique. Ion currents were quantified in protoplasts of the elongation and emerged blade zone of the developing leaf 3 of barley (Hordeum vulgare L.). A time-dependent inward-rectifying K+-selective current was observed almost exclusively in elongation zone protoplasts. The current showed characteristics typical of Shaker-type channels. Instantaneous inward current was highest in the epidermis of the emerged blade and selective for Na+ over K+. Selectivity disappeared, and currents decreased or remained the same, depending on tissue, in response to salt treatment. Net accumulation rates of K+ in cells calculated from patch clamp current-voltage curves exceeded rates calculated from membrane potential and K+ concentrations of cells measured in planta by factor 2.5-2.7 at physiological apoplastic K+ concentrations (10-100 mm). It is concluded that under these conditions, K+ accumulation in growing barley leaf cells is not limited by transport properties of cells. Under saline conditions, down-regulation of voltage-independent channels may reduce the capacity for growth-related K+ accumulation.

KeywordsPlant Sciences
Year of Publication2009
JournalPlant, Cell and Environment
Journal citation32 (12), pp. 1778-1790
Digital Object Identifier (DOI)doi:10.1111/j.1365-3040.2009.02034.x
PubMed ID19682290
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Leverhulme Trust
Funder project or codeSEF
Centre for Crop Genetic Improvement (CGI)
Project: 4967
Optimising nutrient use in cereals
ISSN01407791
PublisherWiley
Grant IDF/00 795/B

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