Abstract
Various attempts have been made to estimate or measure apoplastic pH over the last few decades. These approaches include pH indicators in agar or beads, measurement of the pH of apoplastic fluid, weak acid influx, ion-selective electrodes and optical probes. Each of these has its own applications and limitations, and has contributed to the understanding of the processes taking place in the apoplast in relation to pH changes. However, convincing methods allowing us to probe this cell compartment are still lacking and invite exploration. The distinction between apoplast components is also discussed to clarify the indiscriminate use of the term `apoplastic pH'.
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References
Aked J and Hall L 1993 Effect of powdery mildew infection on concentrations of apoplastic sugars in pea leaves. New Phytol. 123: 283–288.
Aloni B, Daie J and Wyse RE 1988 Regulation of apoplastic pH in source leaves of Vicia faba by gibberellic acid. Plant Physiol. 88: 376–369.
Amtmann A, Jelitto TC and Sanders D 1999 K+-selective inwardrectifying channels and apoplastic pH in barley roots. Plant Physiol. 119: 331–228.
Arif I and Newman IA 1993 Proton efflux from oat coleoptile cells and exchange with wall calcium after IAA or fusicoccin treatment. Planta 189: 377–383.
Ballarin-Denti A and Antoniotti D 1991 An experimental approach to pH measurement in the intercellular free space of higher plant tissues. Experientia 47: 478–482.
Bernstein L. 1971 Method for determining solutes in the cell walls of leaves. Plant Physiol. 47: 361–365.
Bibikova TN, Jacob T, Dahse I and Gilroy S 1998 Localised changes in apoplastic and cytoplasmic pH are associated with root hair development in Arabidopsis thaliana. Development 125: 2925–2934.
Bowling DJF and Edwards A 1984 pH gradients in the stomatal complex of Tradescantia virginiana. J. Exp. Bot. 35: 1641–1645.
Briggs GE 1957 Apparent free space. Annu. Rev. Plant Physiol. 8: 11–30.
Canny MJ 1995 Apoplastic water and solute movement: new roles for an old space. Annu. Rev. Plant Physiol. Plant Mol. Biol. 46: 215–236.
Cleland RE 1973 Auxin-induced hydrogen ion excretion from Avena coleoptiles. Proc. Natl. Acad. Sci. USA 70: 3092–3093.
Cleland RE 1976a Fusicoccin-induced growth and hydrogen ion excretion of Avena coleoptiles: relation to auxin responses. Planta 128: 20–26.
Cleland RE 1976b Kinetics of hormone-induced HC excretion. Plant Physiol. 58: 210–213.
Cleland RE, Virk SS, Taylor D and Björkmn 1990 Calcium, cell wall and growth. In Calcium in Plant Growth and Development. pp. 9–15. Eds RT Leonard and PK Hepler. The American Society of Plant Physiologists Symposium Series, Vol. 4.
Cosgrove DJ and Cleland RE 1983 Solutes in the free space of growing stem tissue. Plant Physiol. 72: 326–331.
Dannel F, Pfeffer H and Marschner H 1995 Isolation of apoplasmic fluid from sunflower leaves and its use for studies on influence of nitrogen supply on apoplasmic pH. J. Plant Physiol. 146: 273–278.
Edwards MC, Smith GN and Bowling DJF 1988 Guard cells extrude protons prior to stomatal opening - a study using fluorescence microscopy and pH micro-electrodes. J. Exp. Bot. 39: 1541–1547.
Felle H 1998 The apoplastic pH of the Zea mays root cortex as measured with pH-sensitive microelectrodes: aspects of regulation. J. Exp. Bot. 49: 987–995.
Glüsenkamp KH, Kosegarten H, Mengel K, Grolig F, Esch A and Goldbach HE 1997 A fluorescein boronic acid conjugate as a marker for borate binding sites in the apoplast of growing roots of Zea mays L. and Helianthus annuus L. In Boron in Soils and Plants. Eds RW Bell and B Rerkasem. pp. 229–235. Kluwer Academic, Dordrecht.
Grignon C and Sentenac H 1991 pH and ionic conditions in the apoplast. Annu. Rev. Plant Physiol. Plant Mol. Biol. 42: 103–128.
Hager A, Menzel H and Krauss A 1971 Versuche und Hypothese zur Primärwirkung des Auxins beim Zellstreckungswachstum. Planta 100: 47–75.
Hanstein S and Felle HH 1999 The influence of atmospheric NH3 on the apoplastic pH of green leaves: a noninvasive approach with pH-sensitive microelectrodes. New Phytol. 143: 333–338.
Hartung W, Radin JW and Hendrix DL 1988 Abscisic acid movement into the apoplastic solution of water stressed cotton leaves: Role of apoplastic pH. Plant Physiol. 86: 908–913.
Hartung W, Weiler EW and Radin JW 1992 Auxin and cytokinins in the apoplastic solution of dehydrated cotton leaves. J. Plant Physiol. 140: 324–327.
Hepler PK and Gunning BES 1998 Confocal fluorescence microscopy of plant cells. Protoplasma 201: 121–157.
Hoffmann B and Kosegarten 1995 FITC-dextran for measuring apoplast pH and apoplastic pH gradients between various cell types in sunflower leaves. Physiol. Plant. 95: 327–335.
Hoffmann B, Plänker R and Mengel K 1992 Measurements of pH in the apoplast of sunflower leaves by means of fluorescence. Physiol. Plant. 84: 146–153.
Hope AB and Stevens 1952 Electrical potential differences in bean roots and their relation to salt uptake. Aust. J. Sci. Res. Ser. B 5: 335–343.
Husted S and Schjoerring JK 1995 Apoplastic pH and ammonium concentration in leaves of Brassica napus L. Plant Physiol. 109: 1453–1460.
Jachetta JJ, Appleby AP and Boermsa L 1986 Use of the pressure vessel to measure concentrations of solutes in apoplastic and membrane-filtered symplastic sap in sunflower leaves. Plant Physiol. 82: 995–999.
Jacobs M and Ray PM 1976 Rapid auxin-induced decrease in free space pH and its relationship to auxin-induced growth in maize and pea. Plant Physiol. 58; 203–209.
Jaillard B, Ruiz L and Arvieu J-C 1996 pH mapping in transparent gel using color indicator videodensitometry. Plant Soil 183: 85–95.
Kochian LV, Shaff JE and Lucas WJ 1989 High affinity K+uptake in maize roots. A lack of coupling with H+ efflux. Plant Physiol. 91: 1202–1011.
Kutschera U 1994 The current status of the acid-growth hypothesis. New Phytol. 126: 549–569.
Lee Y and Satter RL 1988 Effects of temperature on H+ uptake and release during circadian rhythmic movements of excised Samanea motor organs. Plant Physiol. 86: 352–354.
Lee Y and Satter RL 1989 Effects of white, blue, red light and darkness on pH of the apoplast in the Samanea pulvinus. Planta. 178: 31–40.
Marré MT, Romani M, Bellando M and Marré E 1986 Stimulation of weak acid uptake and increase in cell sap pH as evidence for fusicoccin-and K+-induced cytosol alkalinization. Plant Physiol. 82: 316–323.
Marschner H, Römheld V and Ossenberg-Neuhaus H 1982 Rapid method for measuring changes in pH and reducing processes along roots of intact plants. Z. Pflanzenphysiol. Bd. 105: S407–416.
Mühling KH and Sattelmacher B 1995 Apoplastic ion concentration of intact leaves of field bean (Vicia faba) as influenced by ammonium and nitrate. J. Plant Physiol. 147: 81–86
Mühling KH, Plieth C, Hansen UP and Sattelmacher B 1995 Apoplastic pH of intact leaves of Vicia faba as influenced by light. J. Exp. Bot. 46: 377–382.
Mühling KH, Wimmer M and Goldbach HE 1998 Apoplastic and membrane-associated Ca2+ in leaves and roots as affected by boron deficiency. Physiol. Plant. 102: 179–184.
Mulkey TJ and Evans ML 1981 Geotropism in corn roots: evidence for its mediation by differential acid efflux. Science 212: 70–71.
Newman IA, Kochian LV, Grusak MA and Lucas WJ 1987 Fluxes of H+ and K+in corn roots. Characterization and stoichiometric using ion-selective microelectrodes. Plant Physiol. 84: 1177–1184.
Penny MG and Bowling DJF 1975 Direct determination of pH in the stomatal complex of Commelina. Planta. 122: 209–212.
Peters WS and Felle HH 1991a Control of apoplast pH in corn coleoptile segments. I. The endogenous regulation of cell wall pH. J. Plant Physiol. 137: 655–661.
Peters WS and Felle HH 1991b Control of apoplast pH in corn coleoptile segments. II. The effects of various auxins and auxins analogues. J. Plant Physiol. 137: 691–696.
Peters WS and Felle HH 1999 The correlation of profiles of surface pH and elongation growth in maze roots. Plant Physiol. 121: 905–912.
Peters WS, Lommel C and Felle HH 1997 IAA breakdown and its effect on auxin-induced cell wall acidification in maize coleoptile segments. Physiol. Plant. 100: 415–422.
Peters WS, Lüthen H, Böttger M and Felle HH 1998 The temporal correlation of changes in apoplast pH and growth rate in maize coleoptile segments. Aust. J. Plant Physiol. 25: 21–25.
Pfanz and Dietz KJ 1987 A fluorescence method for the determination of the apoplastic proton concentration in intact leaf tissues. J. Plant Physiol. 129: 41–48.
Pilet PE, Versel JM and Mayor G 1983 Growth distribution and surface pH patterns along maize roots. Planta. 158: 398–402.
Pinedo ML, Segarra C and Conde RD 1993 Occurrence of two endoproteinases in wheat leaf intercellular washing fluid. Physiol. Plant. 88: 287–293.
Rayle DL and Cleland R 1970 Enhancement of wall loosening and elongation by acid solutions. Plant Physiol. 46: 250–253.
Richter C and Dainty J 1989 Ion behaviour in plant cell walls. II. Measurement of the Donnan free space, anion-exclusion space, anion-exchange capacity and cation-exchange capacity in delignified Sphagnum russowii cell walls. Can. J. Bot. 67: 460–465.
Rohringer R, Ebrahim-Nsebat F and Wolf G 1983 Proteins in intercellular washing fluids from leaves of barley (Hordeum vulgare L.). J. Exp. Bot. 34: 1589–1605.
Romani G, Marré MT, Bellando M, Alloatti G and Marré E 1985 H+ extrusion and potassium uptake associated with potential hyperpolarization in maize and wheat root segments treated with permanent weak acids. Plant Physiol. 79: 734–739.
Saftner R and Hollander 1975 Use of pH microelectrodes in the study of H+ion secretion in oat coleoptile tissue. Plant Physiol. 56: S1.
Sattelmacher B, Mühling KH and Pennewiß K 1998 The apoplast - its significance for the nutrition of higher plants. Z. Pflanzenernährung Bodenk 161: 485–498.
Sentenac H and Grignon C 1981 A model for predicting ionic equilibrium concentrations in cell walls. Plant Physiol. 68: 415–419.
Sentenac H and Grignon C 1987 Effect of H+ excretion on the surface pH of corn root cells evaluated by using weak acid influx as a pH probe. Plant Physiol. 84: 1367–1372.
Shabala S and Newman I 1999 Light-induced changes in hydrogen, calcium, potassium, and chloride ion fluxes and concentrations from the mesophyll and epidermal tissues of bean leaves. Understanding the ionic basis of light-induced bioelectrogenesis. Plant Physiol. 119: 1115–1124.
Starrach N and Mayer WE 1989 Changes in the apoplastic pH and K+concentration on the Phaseolus pulvinus in situ in relation to rhythmic leaf movements. J. Exp. Bot. 40: 865–873.
Tang C, Longnecker NE, Thomson CJ, Greenway H and Robson AD 1992 Lupin (Lupinus angustifolius L.) and pea (Pisum sativum L.) roots differ widely in their sensitivity to high pH. J. Plant Physiol. 140: 715–719.
Tang C, Longencker NE, Greenway H and Robson AD 1996 Reduced root elongation of Lupinus angustifolius L. by high pH is not due to decreased membrane integrity of cortical cells or low proton production by the roots. Ann. Bot. 78: 409–414.
Taylor DP, Slattery J and Leopold AC 1996 Apoplastic pH in corn root gravitropism: a laser scanning confocal microscopy measurement. Physiol. Plant. 97: 35–38.
Terry ME and Bonner BA 1980 An examination of centrifugation as a method of extracting an extracellular solution from peas, and its use for the study of indole acetic acid-induced growth. Plant Physiol. 66: 321–325.
Tetlow IJ and Farrar JF 1993 Apoplastic sugar concentration and pH in barley infected with brown rust. J. Exp. Bot. 44: 929–936.
Thibaud JB, Davidian JC, Sentenac H, Soler A and Grignon C 1988 H+ co-transports in corn roots as related to the surface pH shift induced by active H+ excretion. Plant Physiol. 88: 1469–1473.
Toulon V, Sentenac H, Thibaus JB, Davidian JC, Moulineau C and Grignon C 1992 Role of apoplast acidification by the H+pump. Planta 186: 212–218.
Weisenseel MH, Dorn A and Jaffe LF 1979 Natural H+ currents traverse growing roots and root hairs of barley (Hordeum vulgare L.). Plant Physiol. 64: 512–518.
Whitaker JE, Haugland RP, Ryan D, Hewitt P, Haugland RP and Prendergast FG. 1992. Fluorescent rhodol derivatives: versatile, photostable labels and tracers. Anal. Biochem. 207: 267–279.
Yu Q, Tang C, Chen Z and Kuo J 1999 Extracting apoplastic fluid from plants roots by centrifugation. New Phytol. 143: 299–304.
Zhang W, Atwell BJ, Patrick JW and Walker NA 1996 Turgordependent efflux of assimilates from coats of developing seed of Phaseolus vulgaris L.: water relations of the cells involved in efflux. Planta 199: 25–33.
Zieschang HE, Küher K and Sievers A 1993 Changing proton concentrations at the surface of gravistimulated Phleum roots. Planta 190: 546–554.
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Yu, Q., Tang, C. & Kuo, J. A critical review on methods to measure apoplastic pH in plants. Plant and Soil 219, 29–40 (2000). https://doi.org/10.1023/A:1004724610550
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DOI: https://doi.org/10.1023/A:1004724610550