Skip to main content
SpringerLink
Log in

Osmotic responses of maize roots

Water and solute relations

  • Published:
Planta Aims and scope Submit manuscript

Abstract

Water and solute relations of excised seminal roots of young maize (Zea mays L) plants, have been measured using the root pressure probe. Upon addition of osmotic solutes to the root medium, biphasic root pressure relaxations were obtained as theoretically expected. The relaxations yielded the hydraulic conductivity Lp r) the permeability coefficient (P sr), and the reflection coefficient (σ sr) of the root. Values of Lp r in these experiments were by nearly an order of magnitude smaller than Lp r values obtained from experiments where hydrostatic pressure gradients were used to induce water flows. The value of P sr was determined for nine different osmotica (electrolytes and nonelectrolytes) which resulted in rather variable values (0.1·10-8–1.7·10-8m·s-1). The reflection coefficient σ sr of the same solutes ranged between 0.3 and 0.6, i.e. σ sr was low even for solutes for which cell membranes exhibit a σ s≈1. Deviations from the theoretically expected biphasic responses occured which may have reflected changes of either P sr or of active pumping induced by the osmotic change. The absolute values of Lp r, P sr, and σ sr have been critically examined for an underestimation by unstirred layer effecs. The data indicate a considerable apoplasmic component for radial movement of water in the presence of hydrostatic gradients and also some solute flow byppassing root protoplasts. In the presence of osmotic gradients, however, there was a substantial cell-to-cell transport of water. Cutting experiments demonstrated that the hydraulic resistance for the longitudinal movement of water was much smaller than for radial transport except for the apical ends of the segments (length=5 to 20 mm). The differences in Lp r as well as the low σ sr values suggest that the simple osmometer model of the root with a single osmotic barrier exhibiting nearly semipermeable properties should be extended for a composite membrane model with hydraulic and osmotic barriers arranged in series and in parallel.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Abbreviations

A r :

root surface area

C m (C X):

solute concentration in the meduum (xylem)

D SS (D CS ):

diffusion coefficient in the stele (cortex)

J Vr :

radia water transport across the root

k wr (k sr):

rate constant of water (solute exchange between root xylem and medium

Lp r :

root hydroaulic conductivity

P r :

root pressure

P sr :

permeability coefficient of root for solute “s”

T 2/Sr1 (T 2/Sr1 ):

half-time of water (solute) exchange between root xylem and medium

V S (V x):

volume of system (xylem)

δ s(δ c):

thickness of unstirred layer in the stele (cortex)

ε S ε X :

elastic modulus of measuring system (xylem)

σ sr :

reflection coefficient of root for solute “s”

Φ:

flow constriction factor; superscripts “en” and “ex” denote flows from the medium into the root xylem or from the xylem into the medium, respectively

References

  • Barry, P.H., Diamond, J.M. (1984) Effects of unstirred layers on membrane phenomena. Physiol. Rev. 64, 763–872

    Google Scholar 

  • Clarkson, D.T., Robards, A.W., Stephens, J.E., Stark, M. (1987) Suberin lamellae in the hypodermis of maize (Zea mays) roots; development and factors affecting the permeability of hypodermal layers. Plant Cell Environ. 10, 83–93

    Google Scholar 

  • Dainty, J. (1963) Water relations of plant cells. Adv. Bot. Res. 1, 279–326

    Google Scholar 

  • Dainty, J. (1985) Water transport throught the root. Acta Hortic. 171, 21–31

    Google Scholar 

  • Dalton, F.N., Raats, P.A.C., Gardner, W.R. (1975) Stimultaneous uptake of water and solutes by plant roots. Agron. J. 67, 334–339

    Google Scholar 

  • Fiscus, E. (1975) The interaction between osmotic and pressure induced water flow in plant roots. Plant Physiol. 59, 1013–1020

    Google Scholar 

  • Fiscus, E.L. (1986) Diurnal changes in volume and solute transport coefficients of Phaseolus roots. Plant Physiol. 80, 752–759

    Google Scholar 

  • Hanson, P.J., Sucoff, E.I., Markhart, A.H. (1985) Quantifying apoplastic flux through red pine root systems using trisodium, 3-hydroxy-5,8,10-pyrenetrisulfonate. Plant Physiol. 77, 21–24

    Google Scholar 

  • Hingson, D.J., Diamond J.M. (1972) Comparison of nonelectrolyte permeability patterns in several epithelia. J. Membr. Biol. 10, 93–135

    Google Scholar 

  • House, C.R. (1974) Water transport in cells and tissues. Edward Arnold, London

    Google Scholar 

  • Hüsken, D., Steudle, E., Zimmermann, U. (1978) Pressure probe technique for measuring water relations of cells in higher plants. Plant Physiol. 61, 158–163

    Google Scholar 

  • Kedem, O., Katchalsky, A. (1963a) Permeability of composite membranes. Part 2: Parallel elements. Trans. Far. Soc. London 59, 1931–1940

    Google Scholar 

  • Kedem, O., Katchalsky, A. (1963b) Permeability of composite membranes. Part 3: Series array of elements. Trans. Far. Soc. London 59, 1941–1953

    Google Scholar 

  • Kramer, P.J. (1983) Water relations of plants. Academic Press, Orlando

    Google Scholar 

  • Miller, D.M. (1985) Studies on root function of Zea mays. III. Xylem sap composition at maximum root pressure provides evidence of active transport into the xylem and a measurement of the reflection coefficient of the root. Plant Physiol. 77, 162–167

    Google Scholar 

  • Passioura, J.B. (1988) Water transport in and to roots. Annu. Rev. Plant Physiol. 39, 245–265

    Google Scholar 

  • Perumalla, C.J., Peterson, C.A. (1986) Deposition of Casparian bands and suberin lamellae in the exodermis and endodermis of young corn and onion roots. Can. J. Bot. 64, 1873–1878

    Google Scholar 

  • Peterson, C.A., Emanuel, M.E., Humphreys, G.B. (1981) Pathway of movement of apoplastic fluorescenct dye tracers through the endodermis at the site of secondary root formation in corn (Zea mays) and broad bean (Vicia faba). Can. J. Bot. 59, 618–625

    Google Scholar 

  • Pitman, M.G. (1976) Ion uptake by plant roots. In: Encyclopedia of plant physiology, N.S., vol 2B: Transport in plants II, pp. 95–128, Lüttge, U., Pitman, M.G., eds. Springer, Berlin

    Google Scholar 

  • Pitman, M.G. (1982) Transport caross plant roots. Q. Rev. Biophys. 15, 481–554

    Google Scholar 

  • Sanderson, J. (1983) Water uptake by different regions of the barley root. Pathways of radial flow in relation to development of the endodermis. J. Exp. Bot. 34, 40–53

    Google Scholar 

  • St. Aubin, G., Canny, M.J., McCully, M.E. (1986) Living vessel elements in the late metaxylem of sheathed maize roots. Ann. Bot. 58, 577–588

    Google Scholar 

  • Steudle, E. (1987a) Water transport in roots. In: Structure and function of plant roots, Kolek, J., ed. Martinus Nijhoff/Dr. W. Junk Publishers, The Hague, in press

    Google Scholar 

  • Steudle, E. (1987b) Pressure probe techniques: Some recent developments. In: Proc. Int. Conf. Measurement of Soil and Plant Water Status, vol 2: Plants, pp. 183–191, Hanks, R.J., Brown, R.W., eds. Utah State University, Logan, Utah, USA, July 1987

    Google Scholar 

  • Steudle, E., Brinckmann, E. (1989) The osmometer model of the root: Water and solute relations of roots of Phaseolus coccineus. Bot. Acta, 102, in press

  • Steudle, E., Jeschke, W.D. (1983) Water transport in barley roots. Planta 158, 237–248

    Google Scholar 

  • Steudle, E., Oren, R., Schulze, E.-D. (1987) Water transport in maize roots. Measurement of hydraulic conductivity, solute permeability, and of reflection coefficients of excised roots using the root pressure probe. Plant Physiol 84, 1220–1232

    Google Scholar 

  • Steudle, E., Typerman, S.D. (1983) Determination of permeability coefficients, reflection coefficients, and hydraulic conductivity of Chara corallina using the pressure probe: Effects of solute concentration. J. Membr. Biol. 75, 85–96

    Google Scholar 

  • Steudle, E., Tyerman, S.D., Wendler, S. (1983) Water relations of plant cells. In: Effects of stress on photosynthesis, pp. 95–109, Marcelle, R., Clijsters, H., van Pouke, M., eds. Martinus Nijhoff/Dr. W. Junk Publishers, Boston

    Google Scholar 

  • Steudle, E., Zimmermann, U. (1984) Water relations of plant cells: Further development of the pressure probe and of techniques for measuring pressure-dependent transport. In: Membrane transport in plants, pp. 73–82, Cram, W.J., Janáček, K., Rybová, R., Sigler, K., eds. Academia, Prague

    Google Scholar 

  • Tyerman, S.D., Steudle, E. (1982) Comparison between osmotic and hydrostatic water flows in a higher plant cell: Determination of hydraulic conductivities and reflection coefficients in isolated epidermis of Tradescantia virginiana. Austr. J. Plant Physiol. 9, 461–479

    Google Scholar 

  • Weatherley, P.J. (1982) Water uptake and flow in roots. In: Encyclopedia of plant physiology, N.S., vol. 12B: Physiological plant ecology II, pp. 79–109, Lange, O.L., Osmond, C.B., Ziegler, H., eds. Springer, Berlin Heidelberg New York

    Google Scholar 

  • Wendler, S., Zimmermann, U. (1982) A new method for the determination of hydraulic conductivity and cell volume of plant cells by pressure clamp. Plant Physiol. 69, 998–1003

    Google Scholar 

  • Yeo, A.R., Yeo, M.E., Flowers, T.J. (1987) The contribution of an apoplastic pathway to sodium uptake by rice roots in saline conditions. J. Exp. Bot. 38, 1141–1153

    Google Scholar 

  • Zimmermann, U., Steudle, E. (1978) Physical aspects of water relations of plant cells. Adv. Bot. Res. 6, 45–117

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Lehrstuhl für Pflanzenökologie, Universität Bayreuth, Universitätsstrasse 30, D-8580, Bayreuth, Federal Republic of Germany

    Ernst Steudle & Jürgen Frensch

Authors
  1. Ernst Steudle
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Jürgen Frensch
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Steudle, E., Frensch, J. Osmotic responses of maize roots. Planta 177, 281–295 (1989). https://doi.org/10.1007/BF00403585

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00403585

Key words

Search

Navigation