Abstract
In many species, roots continue to grow at low water potentials that cause complete inhibition of shoot growth. Recent studies show that the differential sensitivity of root and shoot growth to low water potentials is regulated, at least in part, by the hormone abscisic acid (ABA). When ABA accumulation in maize seedlings at low water potential is inhibited using either fluridone or the vp5 mutant to block carotenoid (and ABA) biosynthesis, primary root elongation is severely inhibited, while shoot growth is promoted as compared with untreated or wild-type seedlings growing at the same water potential. Fluridone-induced inhibition of root elongation at low water potential may be reversed by applying exogenous ABA, confirming the requirement for increased endogenous levels of ABA for the maintenance of root growth under dry conditions. In fluridone-treated seedlings, ABA levels at low water potential decreased to a similar extent throughout the root growth zone, while inhibition of elongation increased with distance from the apex. These results suggest a developmental gradient in tissue responsiveness to endogenous ABA. Current studies suggest that ABA may have a number of roles in maintaining root cell elongation at low water potentials. Firstly, proline is a major contributor to osmotic adjustment in the growth zone of maize primary roots, and its accumulation is partially prevented by treatment with fluridone. This effect can be reversed by adding exogenous ABA. Secondly, activity of the enzyme xyloglucan endotransglycosylase (XET), which is believed to be important for cell wall yielding, is markedly increased in the root growth zone at low water potential, and this response is also inhibited by fluridone, suggesting regulation by ABA.
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References
Creelman RA, Mason HS, Bensen RJ, Boyer JS, Mullet JE (1990) Water deficit and abscisic acid cause differential inhibition of shoot versus root growth in soybean seedlings. Analysis of growth, sugar concentration, and gene expression. Plant Physiology 95: 205–214
Erlandson AGI, Jensen P (1990) Stimulation or inhibition of K+ (86Rb+) influx in wheat roots depending on different ABA treatments. Physiologia Plantarum 78: 331–334
Fry SC, Smith RC, Renwick KJ, Martin DJ, Hodge SK, Matthews KJ (1992) Xyloglucan endotransglycosylase, a new wall-loosening enzyme activity from plants. Biochemistry Journal 282: 821–828
Gaither DH, Lutz DH, Forrence LE (1975) Abscisic acid stimulates elongation of excised pea root tips. Plant Physiology 55: 948–949
Goodwin RH (1972) Studies on roots. V. Effects of indoleacetic acid on the standard root growth pattern in Phleum pratense. Botanical Gazette 133: 224–229
Hartung W, Radin JW, Hendrix DL (1988) Abscisic acid movement into the apoplastic solution of water-stressed cotton leaves. Role of apoplastic pH. Plant Physiology 86: 908–913
Hsiao TC (1973) Plant responses to water stress. Annual Review of Plant Physiology 24: 519–570
Hsiao TC, Bradford KC (1983) Physiological consequences of cellular water deficits. In: Taylor HM, Jordan WR, Sinclair TR (eds) Limitations to efficient water use in crop production. American Society of Agronomy, Madison, USA, pp 227–267
Hsiao TC, Jing J (1987) Leaf and root expansive growth in response to water deficits. In: Cosgrove DJ, Knievel DP (eds) Physiology of cell expansion during plant growth. American Society of Plant Physiologists, Rockville, USA, pp 180–193
Itoh K, Nakamura Y, Kawata H, Yamada T, Ohta E, Sakata M (1987) Effect of osmotic stress on turgor pressure in mung bean root cells. Plant and Cell Physiology 28: 987–994
Jones H, Leigh RA, Tomos AD, Wyn Jones RG (1987) The effect of abscisic acid on cell turgor pressures, solute content and growth of wheat roots. Planta 170: 190–197
Jupp AP, Newman EI (1987) Morphological and anatomical effects of severe drought on the roots of Lolium perenne L. The New Phytologist 105: 393–402
Kutschera U, Bergfeld R, Schopfer P (1987) Cooperation of epidermis and inner tissues in auxin-mediated growth of maize coleoptiles. Planta 170: 168–170
Kuzmanoff KM, Evans ML (1981) Kinetics of adaptation to osmotic stress in lentil (Lens culinaris Med.) roots. Plant Physiology 68: 244–247
Mukherjee I (1974) Effect of potassium on proline accumulation in maize during wilting. Physiologia Plantarum 31: 288–291
Ober ES, Sharp RE (1993) Regulation of proline accumulation by endogenous abscisic acid in maize primary roots at low water potentials. Plant Physiology (in press)
Pesci P (1989) Involvement of C1− in the increase in proline induced by ABA and stimulated by potassium chloride in barley leaf segments. Plant Physiology 89: 1226–1230
Pritchard J, Wyn Jones RG, Tomos AD (1991) Turgor, growth and rheological gradients of wheat roots following osmotic stress. Journal of Experimental Botany 42: 1043–1049
Quarrie SA (1991) Implications of genetic differences in ABA accumulation for crop production. In: Davies WJ, Jones HG (eds) Abscisic acid: physiology and biochemistry. BIOS Scientific Publishers, Oxford, pp 227–244
Rodriguez JL, Davies WJ (1982) The effects of temperature and ABA on stomata of Zea mays L. Journal of Experimental Botany 33: 977–987
Saab IN, Sharp RE, Pritchard J, Voetberg GS (1990) Increased endogenous abscisic acid maintains primary root growth and inhibits shoot growth of maize seedlings at low water potentials. Plant Physiology 93: 1329–1336
Saab IN, Sharp RE, Pritchard J (1992) Effect of inhibition of abscisic acid accumulation on the spatial distribution of elongation in the primary root and mesocotyl of maize at low water potentials. Plant Physiology 99: 26–33
Saugy M, Mayor G, Pilet P-E (1989) Endogenous ABA in growing maize roots: light effects. Plant Physiology 89: 622–627
Sharp RE (1990) Comparative sensitivity of root and shoot growth and physiology to low water potentials. In: Davies WJ, Jeffcoat B (eds) Importance of root to shoot communication in the responses to environmental stress. Monograph 21. British Society for Plant Growth Regulation, Bristol, pp 29–44
Sharp RE, Davies WJ (1979) Solute regulation and growth by roots and shoots of water-stressed maize plants. Planta 147: 43–49
Sharp RE, Hsiao TC, Silk WK (1990) Growth of the maize primary root at low water potentials. II. Role of growth and deposition of hexose and potassium in osmotic adjustment. Plant Physiology 93: 1337–1346
Sharp RE, Silk WK, Hsiao TC (1988) Growth of the maize primary root at low water potentials. I. Spatial distribution of expansive growth. Plant Physiology 87: 50–57
Silk WK, Walker RC, Labavitch J (1984) Uronide deposition rates in the primary root of Zea mays. Plant Physiology 74: 721–726
Spollen WG, Sharp RE (1991) Spatial distribution of turgor and root growth at low water potentials. Plant Physiology 96: 438–443
Sponchiado BN, White JW, Castillo JA, Jones PG (1989) Root growth of four common bean cultivars in relation to drought tolerance in environments with contrasting soil types. Experimental Agriculture 25: 249–257
Stewart CR, Voetberg G (1987) Abscisic acid accumulation is not required for proline accumulation in wilted leaves. Plant Physiology 83: 747–749
Trewavas A (1981) How do plant growth substances work? Plant, Cell and Environment 4: 203–228
Van Volkenburgh E, Davies WJ (1983) Inhibition of light-stimulated leaf expansion by abscisic acid. Journal of Experimental Botany 34: 835–845
Voetberg GS, Sharp RE (1991) Growth of the maize primary root at low water potentials. III. Role of increased proline deposition in osmotic adjustment. Plant Physiology 96: 1125–1130
Watts S, Rodriguez JL, Evans S, Davies WJ (1981) Root and shoot growth of plants treated with abscisic acid. Annals of Botany 47: 595–602
Weaver JE (1926) Root development of field crops. McGraw-Hill, New York Westgate ME, Boyer JS (1985) Osmotic adjustment and the inhibition of leaf, root, stem and silk growth at low water potentials in maize. Planta 164: 540–549
Wu Y, Spollen WG, Sharp RE, Fry SC, Hetherington PR (1993) Root growth maintenance at low water potentials: Increased activity of xyloglucan endo- transglycosylase. Plant Physiology (submitted)
Zeevaart JAD, Creelman RA (1988) Metabolism and physiology of abscisic acid. Annual Review of Plant Physiology and Plant Molecular Biology 39: 439–473
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© 1993 Springer-Verlag Berlin Heidelberg
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Sharp, R.E., Ober, E.S., Wu, Y. (1993). Regulation of Root Growth at Low Water Potentials. In: Jackson, M.B., Black, C.R. (eds) Interacting Stresses on Plants in a Changing Climate. NATO ASI Series, vol 16. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-78533-7_35
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DOI: https://doi.org/10.1007/978-3-642-78533-7_35
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