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

Volkov, 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. (doi: 10.1111/j.1365-3040.2009.02034.x)

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

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Amtmann, Professor Anna
• Authors: Volkov, V., Boscari, A., Clement, M., Miller, A.J., Amtmann, A., and Fricke, W.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Plant, Cell and Environment
• ISSN: 0140-7791