Abstract
Genotypes of sorghum [Sorghum bicolor (L.) Moench] vary in drought resistance. Yet it is not known if their hydraulic resistances vary. The objective of this study was to determine if the hydraulic resistance of a drought-resistant sorghum was the same as that of a drought-sensitive sorghum. Leaf water and osmotic potentials were measured daily, during a 14-d period, in leaves of a drought-resistant (‘KS9’) and a drought-sensitive (‘IA25’) sorghum, which had the roots in pots with a commercial potting soil that was either well watered or allowed to dry. Soil water potential, adaxial stomatal resistance, and transpiration rate were determined daily. Hydraulic resistance of the plants was calculated from the slope of the line relating soil water potential minus leaf water potential versus transpiration rate. When the soil was not watered, the drought-sensitive sorghum had a water potential that averaged −0.50 MPa lower and an osmotic potential that averaged −0.57 MPa lower, but a similar adaxial stomatal resistance (1.19 s mm−1), compared with the drought-resistant sorghum. Seven days after the beginning of the experiment, the water potential of the soil with the drought-sensitive sorghum was −0.25 MPa lower than that of the soil with the drought-resistant sorghum. With the water-limited conditions, the drought-sensitive sorghum depleted the soil-water reserve more quickly and died 2 d before the drought-resistant sorghum. Under well watered conditions, the two sorghums had similar water potentials (−1.64 MPa), osmotic potentials (−2.83 MPa), and adaxial stomatal resistances (0.78 s mm−1). The calculated hydraulic resistance of the two sorghums did not differ and averaged 3.4 × 107 MPa s m−1. The results suggested that the variation in susceptibility to drought between the two genotypes was due to differences in rate of soil-water extraction.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Atkins R E 1983 Registration of 12 sorghum parental lines. Crop Sci. 23, 1229.
Baker J M and Bavel C H M 1986 Resistance of plant roots to water loss. Agron. J. 78, 641–644.
Boyer J S 1985 Water transport. Annu. Rev. Plant Physiol. 36, 473–516.
Bunce J A 1978 Effects of shoot environment on apparent root resistance to water flow in whole soybean and cotton plants. J. Exp. Bot. 29, 595–601.
Cowan I R 1965 Transport of water in the soil-plant-atmosphere system. J. Appl. Ecol. 2, 221–239.
Cowan I R and Milthorpe F L 1971 Permeability of roots and coleoptiles.In Respiration and Circulation. Eds. P L Altman and D S Dittmer. p. 707. Fed. Am. Soc. Exp. Biol., Bethesda, Maryland.
Cruz-Romero G. and Ramos C 1979 Soil water stress and air humidity effects on the root system of sorghum.In The Soil-Root Interface. Eds. J L Harley and R Scott Russell pp 419–420. Academic Press, London.
Fereres E Acevedo E Henderson D W and Hsiao T C 1978 Seasonal changes in water potential and turgor maintenance in sorghum and maize under water stress. Physiol. Plant. 44, 261–267.
Hailey J L, Hiler E A, Jordan W R and van Bavel C H M 1973 Resistance to water flow inVigna sinensis L. (Endl.) at high rates of transpiration. Crop Sci. 13, 264–267.
Kirkham M B 1983 Effect of ABA on the water relations of winter wheat cultivars varying in drought resistance. Physiol. Plant. 59, 153–157.
Krieg D R 1983 Sorghum.In Crop-Water Relations. Eds. I D Teare and M M Peet. pp 351–388. John Wiley and Sons, New York.
Lascano R J and van Bavel C H M 1984 Root water uptake and soil water distribution: test of an availability concept. Soil Sci. Soc. Am. J. 48, 233–237.
Liang G H, Dayton A D, Chu C C and Casady A J 1975 Heritability of stomatal density and distribution on leaves of grain sorghum. Crop Sci. 15, 567–570.
Meyer W S and Ritchie J T 1980 Resistance to water flow in the sorghum plant. Plant Physiol. 65, 33–39.
Myers J K, Foale M A and Done A A 1984 Responses of grain sorghum to varying irrigation frequency in the Ord irrigation area. III. Water relations. Aust. J. Agric Res. 35, 43–52.
Murase H and Merva G E 1979 Hydraulic conductivity of vegetative tissue. Trans. Am. Soc. Agric. Eng. 22, 877–880.
Ross W M, Casady A J, Lawless J R and Barnett F L 1972 29 sorghum parental lines. Crop Sci. 12, 722.
Teare I D and Kanemasu E T 1972 Stomatal-diffusion resistance and water potential of soybean and sorghum leaves. New Phytol. 71, 805–810.
Wright G G, Smith R C G and Morgan J M 1983 Differences between two grain sorghum genotypes in adaptation to drought stress. III. Physiological response. Aust. J. Agric. Res. 34, 637–651.
Author information
Authors and Affiliations
Additional information
Contribution No. 86-249-J from the Kansas Agricultural Experiment Station. The paper is dedicated to the memory of Dr Dan M Rodgers.
Rights and permissions
About this article
Cite this article
Kirkham, M.B. Hydraulic resistance of two sorghums varying in drought resistance. Plant Soil 105, 19–24 (1988). https://doi.org/10.1007/BF02371138
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02371138