Literature confirms that using polyethylene glycol (PEG) as an osmotic agent to imitate water shortage was not so easy in practice, due to PEG toxicity effects and frequent contaminations. Two new approaches were developed to alleviate those problems, one using a raft covered with a membrane to prevent PEG entry in roots, and one using solidified PEG media. The raft trials were done on corn, hexaploid and tetraploid wheat, rye, triticale, oats, barley, Agrotricum; those in solid media, with corn, hexaploid and tetraploid wheat, barley, sorghum and pearl millet. Different species respond differently to PEG-induced osmotic stress. In our trials, the most sensitive cereal was corn, and this finding correlates with the lower osmotic pressure of the sap (a constitutive trait in corn seedlings). Corn responded to osmotic stress by a very poor rate of elongation of the coleoptile, especially when the highest stress (32% PEG) was used. This behavior was also observed in the field in dry years, for example in the Sahel area. Compared to this sensitive cereal species, all other cereals tested were more resistant. Hexaploid and tetraploid wheat, triticale, and Agrotricum kept capacity to elongate roots when submitted to a high osmotic stress, but the higher stress reduced root length considerably. Barley kept rooting ability like other cereals, but was able to develop more aerial biomass, seminal roots, and ramifications. Barley root hair was also longer and covered a higher proportion of the root. Those adaptive features likely explain part of the good adaptation of barley to dry Mediterranean areas. Preliminary results on solid media also showed relationships between drought resistance and the osmoresistance response, at least when comparing species. Roots of species adapted to hot climate, like pearl millet and sorghum, had few seminal roots but displayed a strong gravitropism under osmotic stress. The ease of use of solidified PEG media shows promise for future larger scale trials. Applications of solidified PEG media for research beyond cereal crops is envisioned.
Attree, S.M. 2003. Increasing levels of growth regulator and/or water stress during embryo development. US patent 6627441.
Barnabás, B., Jäger, K., Fehér, A. 2008. The effect of drought and heat on reproductive processes in cereals. Plant Cell Environ. 31:11–38.
Baum, M., Grando, S., Backes, G., Jahoor, A., Sabbagh, A., Ceccarelli, S. 2003. QTLs for agronomic traits in the Mediterranean environment identified in recombinant inbred lines of the cross ‘Arta’ × H. spontaneum 41-1. Theor. Appl. Genet. 107:1215–1225.
Blum, A. 2000. Use of PEG to induce and control plant water deficit in experimental hydroponics culture. http://www.plantstress.com/methods/PEG.htm
Blum, A. 2005. Drought resistance, water use efficiency, and yield potential — are they compatible, dissonant, or mutually exclusive? Aust. J. Agric. Res. 56:1159–1168.
Castonguay, Y., Markhart III, A.H. 1992. Leaf exchange in water-stressed common bean and tepary bean. Crop Sci. 32:980–986.
Ceccarelli, S., Grando, S., Baum, M., Udupa, S.M. 2004. Breeding for drought resistance in a changing climate. In: Challenges and strategies for dryland agriculture. CSSSA Special Publ. no. 32. pp. 167–190.
Grando, S., Ceccarelli, S. 2009. Breeding for resistance to abiotic stresses. In: Ceccarelli, S., Guiamares, E.P., Weltzien, E. (eds), Plant Breeding and Farmer Participation. FAO, Rome, Italy. pp. 391–417.
Hao, X., de Jong, E. 1988. Growth of wheat and barley seedlings at different matric and osmotic potentials. Agron. J. 80:807–811.
Hasse, H., Kany, H.P., Tintinger, R., Maurer, G. 1995. Osmotic virial coefficients of aqueous poly(ethyleneglycol) from laser-light scattering and isopiestic measurements. Macromolecules 28:3540–3552.
Huang, B. 2000. Role of root morphological characteristics in drought resistance of plants. In: Wilkinson, RE. (ed.), Plant-Environment Interactions. Marcel Dekker, NY., USA. pp. 39–64.
McClendon, J.H. 1981. The osmotic pressure of concentrated solutions of polyethylene glycol 6000, and its variation with temperature. J. Exp. Bot. 32:861–866.
Michel, B.E. 1983. Evaluation of the water potential of solutions of polyethylene glycol 8000 both in the absence and presence of other solutes. Plant Physiol. 72:66–70.
Nodichao, L. 1997. Biodiversité racinaire et résistance à la sécheresse [Root system biodiversity and drought resistance]. M.S. thesis. Laval U. 168 pp. (in French)
Plaut, Z., Federman, E. 1985. A simple procedure to overcome polyethylene glycol toxicity on whole plants. Plant Physiol. 79:559–561.
Rajaram, S., van Ginkel, M. 2001. Mexico: 50 years of International Wheat Breeding (chapter 22). In: Bonjean, A.P., Angus, W.J. (eds), The World Wheat Book. A history of wheat breeding. Lavoisier Publishing, Paris, France. pp. 579–608
Sharp, R.E., Silk, W.K., Hsiao, T.C. 1988. Growth of the maize primary root at low water potentials. I. Spatial distribution of expansive growth. Plant Physiol. 87:50–57.
Steuter, A.A., Mozafar, A., Goodin, J.R. 1981. Water potential of aqueous polyethylene glycol. Plant Physiol. 67:64–67.
Szira, F., Bálint, A.F., Börner, A., Galiba, G. 2008. Evaluation of drought-related traits and screening methods at different developmental stages in barley. J. Agron. Crop Sci. 194:334–342.
Tabuchi, T., Kawaguchi, Y., Azuma, T., Nanmori, T., Yasuda, T. 2005. Similar regulation patterns of choline monooxygenase, phosphoethanolamine n-methyltransferase and s-adenosyl-l-methionine synthetase in leaves of the halophyte Atriplex nummularia L. Plant Cell Physiol. 46:505–513.
Teulat, B., Rekika, D., Nachit, M., Monneveux, P. 1997. Comparative adjustment in barley and tetraploid wheats. Plant Breeding 116:519–523.
Tingey, D.T., Stockwell, C. 1977. Semipermeable membrane system for subjecting plants to water-stress. Plant Physiol. 60:58–62.
Walter, H. 1985. Vegetation of the Earth. 3rd ed. Heidelberg Sc. Lib. p. 138.
Winzor, D.J. 2004. Reappraisal of disparities between osmolality estimates by freezing point depression and vapor pressure deficit methods. Biophys. Chem. 107:317–323.
Yan, W., Tinker, N.A. 2005. An integrated biplot analysis system for displaying, interpreting, and exploring genotype-environment interaction. Crop Sci. 45:1004–1016.
Communicated by A. Pécsváradi
About this article
Cite this article
Comeau, A., Nodichao, L., Collin, J. et al. New approaches for the study of osmotic stress induced by polyethylene glycol (PEG) in cereal species. CEREAL RESEARCH COMMUNICATIONS 38, 471–481 (2010). https://doi.org/10.1556/CRC.38.2010.4.3
- osmotic stress