Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-28T20:46:54.715Z Has data issue: false hasContentIssue false

Response of the components of sugar beet leaf water potential to a drying soil profile

Published online by Cambridge University Press:  27 March 2009

Kay F. Brown
Affiliation:
Broom's Barn Experimental Station, Higham, Bury St Edmunds, Suffolk, IP28 6NP
M. McGowan
Affiliation:
Nottingham University School of Agriculture, Sutton Bonington, Loughborough, Leicestershire, LE12 5RD
M. J. Armstrong
Affiliation:
Broom's Barn Experimental Station, Higham, Bury St Edmunds, Suffolk, IP28 6NP

Summary

For many field-grown crops, including sugar beet, there is little information on the seasonal changes in leaf water potential and its components as the soil dries. Therefore, seasonal changes in leaf water, osmotic and turgor potentials of sugar beet were measured in two seasons, in crops that experienced differing degrees of soil moisture stress. In 1983 potentials of crops exposed to early and late droughts were compared with those of irrigated crops, and in 1984 measurements were made in a non-irrigated crop. In the irrigated crop the midday leaf water potential changed little during the season, except in response to fluctuating evaporative demand. In the drought and non-irrigated treatments there was a sharp fall in leaf water potential as soon as the soil water potential decreased. The size of the midday leaf water potential was primarily determined by soil dryness. However, the leaf water potential did not decrease below about — 1·5 MPa in either year. The leaf osmotic potential declined at the same time as the leaf water potential, but the extent to which this happened differed in the two years. Only in the 1984 non-irrigated crop did the osmotic potential continue to decrease as the soil dried, suggesting that osmotic adjustment had taken place in 1984 but not in 1983. Thus higher turgor was maintained in the 1984 crop than in the 1983 drought-affected crops. Some turgors were recorded as apparently negative in 1983.

Since the leaf water potential declined to a minimum of about — 1·5 MPa, the soil water potential minima were also about — 1·5 MPa. However, deeper soil was not dried to this extent, suggesting that the extra resistance for water uptake from deep soil was limiting or the rooting density was too low.

The pattern of recovery of leaf water potential overnight suggested that the rhizosphere resistance to water movement was small, even as the soil dried. However, measurement of stem water potentials in 1984 indicated that a significant resistance to water flow existed within the aerial part of sugar beet plants. This shows that the use of the water potential in leaves as an estimate of that in stems or roots can be misleading.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1987

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Barrs, H. D. (1968). Determination of water deficits in plant tissues. In Water Deficits and Plant Growth, vol. 1, Development, Control and Measurement (ed. Kozlowski, T. T.), pp. 235368. London and New York: Academic Press.Google Scholar
Begg, J. E. & Turner, N. C. (1970). Water potential gradients in field tobacco. Plant Physiology 46, 343346.CrossRefGoogle ScholarPubMed
Biscoe, P. V. (1972). The diffusion resistance and water status of leaves of Beta vulgaris. Journal of Experimental Botany 23, 930940.CrossRefGoogle Scholar
Brown, K. F. (1986). Water use and fibrous root growth of sugar beet. Ph.D. thesis, University of Nottingham.Google Scholar
Brown, K. F., Messem, A. B., Dunham, R. J. & Biscoe, P. V. (1987). Effect of drought on growth and water use of sugar beet. Journal of Agricultural Science, Cambridge 109, 421435.CrossRefGoogle Scholar
Denmead, O. T. & Millar, B. D. (1976). Water transport in wheat plants in the field. Agronomy Journal 68, 297303.CrossRefGoogle Scholar
Durrant, M. J., Draycott, A. P. & Milford, G. F. J. (1978). Effect of sodium fertiliser on water status and yield of sugar beet. Annals of Applied Biology 88, 321328.CrossRefGoogle Scholar
Hsaio, T. C., Acevedo, E., Fereres, E. & Henderson, D. W. (1976). Water stress, growth and osmotic adjustment. Philosophical Transactions of the Royal Society, London B 273, 479500.Google Scholar
Lawlor, D. W. & Milford, G. F. J. (1973). The effect of sodium on the growth of water-stressed sugar beet. Annals of Botany 37, 597604.CrossRefGoogle Scholar
Lawlor, D. W. & Milford, G. F. J. (1975). The control of water and carbon dioxide flux in water-stressed sugar beet. Journal of Experimental Botany 266, 657665.CrossRefGoogle Scholar
Leach, J. E., Woodhead, T. & Day, W. (1982). Bias in pressure chamber measurements of leaf water potential. Agricultural Meteorology 27, 257263.CrossRefGoogle Scholar
McGowan, M., Blanch, P., Gregory, P. J. & Haycock, D. (1984). Water relations of wheat. 5. The root system and osmotic adjustment in relation to crop evaporation. Journal of Agricultural Science, Cambridge 102, 415425.CrossRefGoogle Scholar
McGowan, M. & Tzimas, E. (1985). Water relations of winter wheat: the root system, petiolar resistance and development of a root abstraction equation. Experimental Agriculture 21, 377388.CrossRefGoogle Scholar
Markhart, A. H., Sionit, N. & Siedow, J. N. (1981). Cell wall dilution: an explanation of apparent negative turgor potentials. Canadian Journal of Botany 59, 17221725.CrossRefGoogle Scholar
Milford, G. F. J., Cormack, W. F. & Durrant, M. J. (1977). Effects of sodium chloride on water status and growth of sugar beet. Journal of Experimental Botany 28, 13801388.CrossRefGoogle Scholar
Milford, G. F. J. & Lawlor, D. W. (1975). Effects of varying air and soil moisture on the water relations and growth of sugar beet. Annals of Applied Biology 80, 93102.CrossRefGoogle Scholar
Neumann, H. H., Thurtell, G. W. & Stevenson, K. R. (1974). In situ measurements of leaf water potential and resistance to water now in corn, soybean and sunflower at several transpiration rates. Canadian Journal of Plant Science 54, 175184.CrossRefGoogle Scholar
Plaut, Z. & Heuer, B. (1985). Adjustment, growth, photosynthesis and transpiration of sugar beet plants exposed to saline conditions. Field Crops Research 10, 113.CrossRefGoogle Scholar
Scholander, P. F., Hammel, H. T., Bradstreet, E. D. & Hemmingsen, E. A. (1965). Sap pressure in vascular plants. Science 148, 339346.CrossRefGoogle ScholarPubMed
Taylor, H. M. & Klepper, B. (1975). Water uptake by cotton root systems: an examination of assumptions in the single root model. Soil Science 120, 5767.CrossRefGoogle Scholar
Turner, N. C. & Jones, M. M. (1980). Turgor maintenance by osmotic adjustment: a review and evaluation. In Adaptation of Plants to Water and High Temperature Stress (ed. Turner, N. C. and Kramer, P. J.), pp. 87103. New York: John Wiley.Google Scholar
Tyree, M. T. (1976). Negative turgor pressure in plant cells: fact or fallacy. Canadian Journal of Botany 54, 27382746.CrossRefGoogle Scholar
Wallace, J. S., Clark, J. A. & McGowan, M. (1983). Water relations of winter wheat. 3. Components of leaf water potential and the soil-plant water potential gradient. Journal of Agricultural Science, Cambridge 100, 581589.CrossRefGoogle Scholar
Whitehead, D. (1975). The effects of water stress on photosynthesis and growth of plants. Ph.D. thesis, University of London.Google Scholar