Abstract
An ion-selective vibrating-microelectrode system, which was originally used to measure extracellular Ca2+ gradients generated by Ca2+ currents, was used to study K+, H+ and Ca2+ transport in intact maize (Zea mays L.) roots and individual maize suspension cells. Comparisons were made between the vibrating ion-selective microelectrode, and a technique using stationary ion-selective microelectrodes to measure ionic gradients in the unstirred layer at the surface of plant roots. The vibrating-microelectrode system was shown to be a major improvement over stationary ion-selective microelectrodes, in terms of sensitivity and temporal resolution. With the vibrating ion microelectrode, it was easy to monitor K+ influxes into maize roots in a background K+ concentration of 10 mM or more, while stationary K+ electrodes were limited to measurements in a background K+ concentration of 0.3 mM or less. Also, with this system it was possible to conduct a detailed study of root Ca2+ transport, which was previously not possible because of the small fluxes involved. For example, we were able to investigate the effect of the excision of maize roots on Ca2+ influx. When an intact maize root was excised from the seedling at a position 3 cm from the site of measurement of Ca2+ transport, a rapid fourfold stimulation of Ca2+ influx was observed followed by dramatic oscillations in Ca2+ flux, oscillating between Ca2+ influx and efflux. These results clearly demonstrate that wound or perturbation responses of plant organs involve transient alterations in Ca2+ transport, which had previously been inferred by demonstrations of touch-induced changes in cytoplasmic calcium. The sensitivity of this system allows for the measurement of ion fluxes in individual plant cells. Using vibrating K+ and H+electrodes, it was possible to measure H+efflux and both K+ influx and efflux in individual maize suspension cells under different conditions. The availability of this technique will greatly improve our ability to study ion transport at the cellular level, in intact plant tissues and organs, and in specialized cells, such as root hairs or guard cells.
Similar content being viewed by others
Abbreviations
- ΔX:
-
amplitude of vibration
Referencess
Braam, J., Davis, R.W. (1990) Rain, wind and touch-induced expression of calmodulin and calmodulin-like genes in Arabidopsis. Cell. 60, 357–364
Bush, D.R., Jacobson, L. (1986) Potassium transport in suspension culture cells and protoplasts of carrot. Plant Physiol. 81, 1022–1026
Carslaw, H.S., Jaeger, J.C. (1959) Conduction of heat in solids, 2nd edn. Clarendon Press, Oxford
Crank, J. (1975) The mathematics of diffusion. Clarendon Press, Oxford
Gronewald, J.W., Hanson, J.B. (1980) Sensitivity of the proton and ion transport mechanisms of corn roots to injury. Plant Sci. Lett. 18, 143–150
Gronewald, J.W., Cheeseman, J.M., Hanson, J.B. (1979) Comparison of the responses of corn root tissue to fusicoccin and washing. Plant Physiol. 63, 255–259
Hanson, J.B., Rincon, M., Rogers, S.A. (1986) Controls of calcium influx in corn root cells. In: Molecular and cellular aspects of calcium in plant development, pp. 253–260, Trewavas, A.J., ed. Plenum Press, New York London
Harned, H.S., Owen, B.B. (1958) The physical chemistry of electrolyte solutions. Reinhold Press, New York
Henriksen, G.H., Bloom, A.J., Spanswick, R.M. (1990) Measurement of net fluxes of ammonium and nitrate at the surface of barley roots using ion-selective microelectrodes. Plant Physiol. 39, 196–203
Henriksen, G.H., Raman, D.R., Walker, L.P., Spanswick, R.M. (1992) Measurement of net fluxes of ammonium and nitrate at the surface of barley roots using ion-selective microelectrodes. II. Patterns of uptake along the root axis and evaluation of the microelectrode flux estimation technique. Plant Physiol. 99, 734–747
Huang, J.W., Shaff, J.E., Grunes, D.L., Kochian, L.V. (1992a) Al effects on calcium fluxes at the root apex of Al-tolerant and Al-sensitive wheat cultivars. Plant Physiol 98, 230–237
Huang, J.W., Grunes, D.L., Kochian, L.V. (1992b) Aluminum effects on the kinetics of calcium uptake into cells of the wheat root apex. Quantification of calcium fluxes using a calciumselective vibrating microelectrode. Planta 188, 414–421
Knight, M.R., Campbell, A.K., Smith, S.M., Trewavas, A.J. (1991) Transgenic plant aequorin reports the effects of touch and coldshock and elicitors on cytoplasmic calcium. Nature 352, 524–526
Kochian, L.V., Lucas, W.J. (1982) Potassium transport in corn roots. I. Resolution of kinetics into a saturable and linear component. Plant Physiol. 70, 1723–1731
Kochian, L.V., Shaff, J.E., Lucas, W.J. (1989) High-affinity K+ uptake in maize roots: A lack of coupling with H+ efflux. Plant Physiol. 91, 1202–1211
Kühtreiber, W.M., Jaffe, L.F. (1990) Detection of extracellular calcium gradients with a calcium-specific vibrating electrode. J. Cell Biol. 110, 1565–1573
Lucas, W.J. (1975) Analysis of the diffusion symmetry developed by the alkaline and acid bands which form at the surface of Chara corallina cells. J. Exp. Bot. 26, 271–286
Lucas, W.J., Kochian, L.V. (1986) Ion transport processes in corn roots: An approach utilizing microelectrode techniques. In: Advanced agricultural instrumentation, pp. 402–425, Gensler, W.G., ed. Martinus Nijhoff Publishers, Dordrecht Boston Lancaster
Miyasaka, S.C., Kochian, L.V., Shaff, J.E., Foy, C.D. (1989) Mechanisms of aluminum tolerance: An investigation of genotypic differences in rhizosphere pH, potassium and proton fluxes, and membrane potentials. Plant Physiol. 91, 1188–1196
Murashige, T., Skoog, F. (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15, 473–497
Newman, I.A., Kochian, L.V., Grusak, M.A., Lucas, W.J. (1987) Fluxes of H+ and K+ in corn roots: Characterization and stoichiometries using ion-selective microelectrodes. Plant Physiol. 84, 1177–1184
Robinson, R.A., Stokes, R.H. (1959) Electrolyte solutions. Butterworths, London
Rodriguez-Navarro, A., Blatt, M.R., Slayman, C.L. (1986) A potassium-proton symport in Neurospora crassa. J. Gen. Physiol. 87, 649–674
Ryan, P.R., Newman, I.A., Shields, B. (1990) Ion fluxes in corn roots measured by microelectrodes with ion-specific liquid membranes. J. Membr. Sci. 53, 59–69
Schiefelbein, J.W., Shipley, A., Rowse, P. (1992) Calcium influx at the tip of growing root-hair cells of Arabidopsis thaliana. Planta 187, 455–459
Siddiqi, M.Y., Glass, A.D.M., Ruth, T.J., Rufty, T.W. (1990) Studies of the uptake of nitrate in barley. I. Kinetics of 13NO3- influx. Plant Physiol. 93, 1426–1432
Wang, M., Glass, A.D.M., Siddiqi, M.Y. (1991) The mechanism of ammonium uptake by rice roots. Plant Physiol. 96, S145
Zocchi, G., Hanson, J.B. (1982) Calcium influx into corn roots as a result of cold shock. Plant Physiol. 70, 318–319
Author information
Authors and Affiliations
Additional information
The authors would like to thank Richard Sanger for his invaluable work on the design and improvement of the ion-selective vibratingmicroelectrode system. The research presented here was supported in part by U.S. Department of Agriculture Competitive Grant No. 90-37261-5411 to Leon Kochian and William Lucas.
Rights and permissions
About this article
Cite this article
Kochian, L.V., Shaff, J.E., Kühtreiber, W.M. et al. Use of an extracellular, ion-selective, vibrating microelectrode system for the quantification of K+, H+, and Ca2+ fluxes in maize roots and maize suspension cells. Planta 188, 601–610 (1992). https://doi.org/10.1007/BF00197055
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00197055