Abstract
To elucidate the role of aquaporins in the control of the root pressure, we tested the effects of HgCl2 (aquaporin blocker) at concentrations from 10−8 to 10−2 M on the exudation rate (J w). Experiments were performed with detached roots of 5–7-day-old etiolated maize (Zea mays L.) seedlings. HgCl2 suppressed exudation by 50–70% at the concentration of 2 × 10−5 M. At the concentration of 2.5 × 10−4 M, HgCl2 reduced J w during first 20–40 min, but in 2 h, it activated exudation by ten and more times. In this case, the root and osmotic pressures of the exudates increased by 1.5 times. The hydraulic conductance reduced approximately by 30% during first 30 min and increased severalfold in 2 h. The temperature coefficient (Q10) of J w attained 14 in 2 h. At the concentration of 10−2 M, HgCl2-induced acceleration of exudation was replaced by its inhibition essentially immediately. We suggested that a driving force for HgCl2-induced stimulation of the J w might be an increase in the osmotic component of the root pressure or the involvement of its nonosmotic (so-called metabolic) component. The results allow a supposition that aquaporins are involved in the control of water transport in the root.
Similar content being viewed by others
Abbreviations
- J m :
-
the rate of exudation
- L P :
-
hydraulic conductance
- MC:
-
metabolic component
- OP:
-
osmotic pressure
- Q10 :
-
temperature coefficient
- RP:
-
root pressure
References
Pickard, W.F., The Riddle of Root Pressure: 1. Putting Maxwell’s Demon to Rest, Funct. Plant Biol., 2003, vol. 30, pp. 121–134.
Pickard, W.F., The Riddle of Root Pressure: 2. Root Exudation at Extreme Osmolalites, Funct. Plant Biol., 2003, vol. 30, pp. 135–141.
Javot, H. and Maurel, C., The Role of Aquaporins in Root Water Uptake, Ann. Bot., 2002, vol. 90, pp. 301–313.
Maurel, C., Tacnet, F., Guclu, J., Guern, J., and Ripoche, P., Purified Vesicles of Tobacco Cell Vacuolar and Plasma Membranes Exhibit Dramatically Different Water Permeability and Water Channel Activity, Proc. Natl. Acad. Sci. USA, 1997, vol. 94, pp. 7103–7108.
Wan, X. and Zwizek, J.J., Mercuric Chloride Effects on Root Water Transport in Aspen Seedlings, Plant Physiol., 1999, vol. 121, pp. 939–946.
Niemietz, C.M. and Tyerman, S.D., Characterization of Water Channels in Wheat Root Membrane Vesicles, Plant Physiol., 1997, vol. 115, pp. 561–567.
Maggio, A. and Joly, R.J., Effects of Mercuric Chloride on the Hydraulic Conductivity of Tomato Root Systems, Plant Physiol., 1995, vol. 109, pp. 331–335.
Zhang, W.-H. and Tyerman, S.D., Inhibition of Water Channels by HgCl2 in Intact Wheat Roots, Plant Physiol., 1999, vol. 120, pp. 849–858.
Finkelstein, A., Water Movement through Lipid Bilayers, Pores, and Plasma Membranes. Theory and Reality, Distinguished Lecture Series of the Society of General Physiologists, New York: Wiley and Sons, 1987, vol. 4.
Johansson, I., Karlsson, M., Shukla, V.K., Chrispeels, M.J., Larsson, C., and Kjellbom, P., Water Transport Activity of the Plasma Membrane Aquaporins PM28A Is Regulated by Phosphorylation, Plant Cell, 1998, vol. 10, pp. 451–459.
Bozhko, K.N., Zhestkova, I.M., Trofimova, M.S., Kholodova, V.P., and Kuznetsov, Vl.V., Aquaporin Content in Cell Membranes of Mesembryanthemum crystallinum as Affected by Plant Transition from C3 to CAM Type of Photosynthesis, Russ. J. Plant Physiol., 2004, vol. 51, pp. 798–805.
Gerbeau, P., Amodeo, G., Henzler, T., Santoni, V., Ripocke, P., and Maurel, C., The Water Permeability of Arabidopsis Plasma Membrane Is Regulated by Divalent Cations and pH, Plant J., 2002, vol. 30, pp. 71–81.
Moshelion, M., Moran, N., and Chaumont, F., Dynamic Changes in the Osmotic Water Permeability of Protoplast Plasma Membrane, Plant Physiol., 2004, vol. 135, pp. 2301–2317.
Luu, D.-T. and Maurel, C., Aquaporins in a Challenging Environment: Molecular Gears for Adjusting Plant Water Status, Plant, Cell Environ., 2005, vol. 28, pp. 85–96.
Niemietz, C.M. and Tyerman, S.D., New Potent Inhibitors of Aquaporins: Silver and Gold Compounds Inhibit Aquaporins of Plant and Human Origin, FEBS Lett., 2002, vol. 531, pp. 443–447.
Preston, G.M., Jung, J.S., Guggino, W.B., and Agre, P., The Mercury-Sensitive Residue at Cysteine 189 in the CHIP28 Water Channel, J. Biol. Chem., 1993, vol. 268, pp. 17–20.
Tyerman, S.D., Bohnert, H.J., Maurel, C., Steudle, E., and Smith, J.A.C., Plant Aquaporins: Their Molecular Biology, Biophysics and Significance for Plant Water Relations, J. Exp. Bot., 1999, vol. 50, pp. 1055–1071.
Patra, M. and Sharma, A., Mercury Toxicity in Plants, Bot. Rev., 2000, vol. 66, pp. 379–422.
Steudle, E., Water Uptake by Roots: Effects of Water Deficit, J. Exp. Bot., 2000, vol. 51, pp. 1531–1542.
Gamalei, Yu.V., Transportnaya sistema sosudistykh rastenii. Proiskhozhdenie, struktura, funktsii, razvitie, analiz raznoobraziya tipov po taksonomicheskim i ekologo-geograficheskim gruppam rastenii, evolyutsiya i ekologicheskaya spetsializatsiya transportnoi sistemy (Transport System of Vascular Plants. Origin, Structure, Functions, Development, Analysis of Type Diversity in Taxonomic, Ecological, and Geographic Groups, Evolution, and Ecological Specialization of the Transport System), St. Petersburg: St. Petersburg Gos. Univ., 2004.
Borisova, T.A., Lazareva, N.P., and Zholkevich, V.N., Possible Physiological Role of Endodermal Water Potential Jump in the Root System, Sov. Plant Physiol., 1984, vol. 31, pp. 1092–1098.
Scholander, P.F., Hammel, H.T., Hemmingsen, E.A., and Bradstreet, E.D., Sap Pressure in Vascular Plants, Science, 1965, vol. 148, pp. 339–346.
Zholkevich, V.N., Zhukovskaya, N.V., and Popova, M.S., The Involvement of Protein Kinases and Protein Phosphatases in Signal Transduction during Neurotransmitter-Induced Stimulation of Root Water-Pumping Activity, Russ. J. Plant Physiol., 2007, vol. 54, pp. 487–490.
Hales, S., Vegetable Staticks, London: Inneys W.J. and Woodward T., 1727.
Skoog, F., Broyer, T.C., and Grossenbacher, K.A., Effect of Auxin on Rates, Periodicity, and Osmotic Relations in Exudation, Am. J. Bot., 1938, vol. 25, pp. 749–759.
Wallace, A., Ashcroft, R.T., and Lunt, O.R., Root Pressure and Exudation in Tobacco. II. The Osmometer Theory of Exudation, Current Topics in Plant Nutrition, Wallace, A., Ed., Los Angeles, 1966, pp. 136–143.
Quintero, J.M., Fournier, J.M., and Benlloch, M., Water Transport in Sunflower Root Systems: Effects of ABA, Ca2+ Status and HgCl2, J. Exp. Bot., 1999, vol. 50, pp. 1607–1612.
Zholkevich, V.N., Sinitsyna, Z.A., Peisakhzon, B.I., Abutalybov, V.F., and D’yachenko, I.V., Nature of Root Pressure, Sov. Plant Physiol., 1979, vol. 26, pp. 978–993.
Zholkevich, V.N., Transport vody v rastenii i ego endogennaya regulyatsiya. 61-e Timiryazevskoe chtenie (Water Transport and Its Endogenous Regulation, the 61st Timiryazev Lecture), Moscow: Nauka, 2001.
Zholkevich, V.N., Popova, M.S., and Zhukovskaya, N.V., Stimulatory Effects of Adrenalin and Noradrenalin on Root Water-Pumping Activity and the Involvement of G-Proteins, Russ. J. Plant Physiol., 2007, vol. 54, pp. 790–796.
Yasui, M., Kwon, T.-H., Knepper, M.A., Nielsen, S., and Agre, P., Aquaporin-6: An Intracellular Vesicle Water Channel Protein in Renal Epithelia, Proc. Natl. Acad. Sci. USA, 1999, vol. 96, pp. 5808–5813.
Encyclopedia of Plant Physiology, vol. 1, Transport in Plants. I. Phloem Transport, Zimmermann, M.H. and Milburn, J.A., Eds., Berlin: Springer-Verlag, 1975.
Cais, O., Sedlacek, M., Horak, M., Dittert, I., and Vyklicky, L., Jr., Temperature Dependence of NR1/NR2B NMDA Receptor Channels, Neuroscience, 2008, vol. 151, pp. 428–438.
Anderson-Teixeira, K.J., Vitousek, P.M., and Brown, J.H., Amplified Temperature Dependence in Ecosystems Developing on the Lava Flows of Mauna Loa, Hawai’i, Proc. Natl. Acad. Sci. USA, 2008, vol. 105, pp. 228–233.
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © A.G. Dustmamatov, V.N. Zholkevich, 2008, published in Fiziologiya Rastenii, 2008, Vol. 55, No. 6, pp. 901–907.
Rights and permissions
About this article
Cite this article
Dustmamatov, A.G., Zholkevich, V.N. Effects of HgCl2 on principal parameters of exudation from maize detached root system. Russ J Plant Physiol 55, 814–820 (2008). https://doi.org/10.1134/S1021443708060113
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1021443708060113