Hostname: page-component-848d4c4894-75dct Total loading time: 0 Render date: 2024-05-05T05:18:19.224Z Has data issue: false hasContentIssue false

Incubation under fluctuating temperatures reduces mean base water potential for seed germination in several non-cultivated species

Published online by Cambridge University Press:  22 February 2007

Roberto Huarte*
Affiliation:
Cátedra de Fisiología Vegetal, Facultad de Ciencias Agrarias, Universidad Nacional de Lomas de Zamora, Ruta 4 Kilometro Z. Llaudllol. CP (1836), República Argentina
Roberto L. Benech-Arnold
Affiliation:
IFEVA, Cátedra de Cerealicultura, Facultad de Agronomía, CONICET/Universidad de Buenos Aíres, Avenida San Martín 4453, CP (1417), Ciudad de Buenos Aíres, República Argentina
*
*Correspondence: Fax: +54 11 4282 0233 Email: rhuarte@yahoo.com

Abstract

Seeds of Carduus acanthoides, Cynara cardunculus, Cirsium vulgare, Brassica campestris, and Sisymbrium altissimum were incubated at a range of decreasing osmotic potentials (Ψo) under fluctuating temperatures or the median temperature of the fluctuation cycle. Fluctuating temperatures promoted total seed germination in water and at reduced osmotic potential. Total germination was reduced as the Ψo decreased. However, this trend was smallest under fluctuating temperatures, signalling a higher tolerance of seeds to reduced osmotic potential. Effects of osmoticum and temperature were modelled with the hydrotime model. The parameters estimated from the model, the hydrotime constant (θH), the mean base water potential Ψb(50) and its standard deviation (σΨb) gave good descriptions of germination time courses. For all species, incubation under fluctuating temperatures shifted Ψb(50) values downwards without modifying their distribution substantially. This accounted for the greater tolerance of germination to reduced Ψo under fluctuating temperatures. To confirm that these effects were mediated by temperature fluctuations per se, the behaviour of C. acanthoides and C. cardunculus incubated at the minimum, the mean and the maximum temperature of the fluctuation cycle was also analysed. Constant maximum and minimum temperatures of the cycle did not stimulate germination, nor did they shift Ψb(50) towards more negative values. The hydrotime model provides a physiologically based quantitative description for germination promotion due to fluctuating temperature.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2005

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

Alvarado, V. and Bradford, K.J. (2002) A hydrothermal time model explains the cardinal temperatures for seed germination. Plant, Cell and Environment 25, 10611069.CrossRefGoogle Scholar
Batlla, D., Verges, V., Benech-Arnold, R.L. (2003) A quantitative analysis of seed responses to cycle-doses of fluctuating temperatures in relation to dormancy: development of a thermal time model for Polygonum aviculare L. seeds. Seed Science Research 13, 197207.CrossRefGoogle Scholar
Benech-Arnold, R.L., Ghersa, C.M., Sánchez, R.A. and Insausti, P. (1990) Temperature effects on dormancy release and germination rate in Sorghum halepense (L.) Pers. seeds: a quantitative analysis. Weed Research 30, 8189.CrossRefGoogle Scholar
Benech-Arnold, R.L., Kristof, G., Steinbach, H.S., Sánchez, R.A. (1995) Fluctuating temperatures have different effects on embryonic sensitivity to ABA in Sorghum varieties with contrasting pre-harvest susceptibility. Journal of Experimental Botany 46, 711717.CrossRefGoogle Scholar
Benech-Arnold, R.L., Sánchez, R.A., Forcella, F., Kruk, B.C. and Ghersa, C.M. (2000) Environmental control of dormancy in weed seed banks in soil. Field Crops Research 67, 105122.CrossRefGoogle Scholar
Bradford, K.J. (1990) A water relations analysis of seed germination rates. Plant Physiology 94, 840849.CrossRefGoogle ScholarPubMed
Bradford, K.J. (1995) Water relations in seed germination. pp. 351396. Kigel, J.;, Galili, G. (Eds) Seed development and germination. New York, Marcel Dekker.Google Scholar
Bradford, K.J. (1996) Population-based models describing seed dormancy behaviour: implications for experimental design and interpretation. pp. 313339. Lang, G.A.Plant dormancy: Physiology, biochemistry and molecular biology. Wallingford, CAB International.Google Scholar
Bradford, K.J. and Somasco, O.A. (1994) Water relations of lettuce seed thermoinhibition. I. Priming and endosperm effects on base water potential. Seed Science Research 4, 110.CrossRefGoogle Scholar
Christensen, M., Meyer, S.E. and Allen, P.S. (1996) A hydrothermal time model of seed after-ripening in Bromus tectorum L. Seed Science Research 6, 155163.CrossRefGoogle Scholar
Dutta, S. and Bradford, K.J. (1994) Water relations of lettuce seed thermoinhibition. II. Ethylene and endosperm effects on base water potential. Seed Science Research 4, 1118.CrossRefGoogle Scholar
Ekstam, B., Johannesson, R. and Milberg, P. (1999) The effects of light and number of diurnal temperature fluctuations on germination of Phragmites australis. Seed Science Research 9, 165170.CrossRefGoogle Scholar
Forcella, F. and Wood, H. (1986) Sequential flowering of thistles (Cynareae, Asteraceae) in southern Australia. Australian Journal of Botany 34, 455461.CrossRefGoogle Scholar
Groves, R.H. and Kaye, P.E. (1989) Germination and phenology of seven introduced thistle species in southern Australia. Australian Journal of Botany 37, 351359.CrossRefGoogle Scholar
Gummerson, R.J. (1986) The effect of constant temperatures and osmotic potentials on the germination of sugar beet. Journal of Experimental Botany 37, 729741.CrossRefGoogle Scholar
Kebreab, E. and Murdoch, A.J. (1999) Modelling the effects of water stress and temperature on germination rate of Orobanche aegyptiaca seeds. Journal of Experimental Botany 50, 655664.CrossRefGoogle Scholar
Kruk, B.C., Benech-Arnold, R.L. (2000) Evaluation of dormancy and germination responses to temperature in Carduus acanthoides and Anagallis arvensis using a screening system, and relationship with field-observed emergence patterns. Seed Science Research 10, 7788.CrossRefGoogle Scholar
Michel, B.E. (1983) Evaluation of the water potentials of solutions of polyethylene glycol 8000 both in the absence and presence of other solutes. Plant Physiology 72, 6670.CrossRefGoogle ScholarPubMed
Ni, B.R. and Bradford, K.J. (1992) Quantitative models characterizing seed germination responses to abscisic acid and osmoticum. Plant Physiology 98, 10571068.CrossRefGoogle ScholarPubMed
Ni, B.R. and Bradford, K.J. (1993) Germination and dormancy of abscisic acid and gibberellin-deficient mutant tomato (Lycopersicon esculentum) seeds. Sensitivity of germination to abscisic acid, gibberellin, and water potential. Plant Physiology 101, 607617.CrossRefGoogle ScholarPubMed
Probert, R.J. (1992) The role of temperature in germination ecophysiology. pp. 285325. in Fenner, M. (Ed.) Seeds. The ecology of regeneration in plant communities. Wallingford, CAB International.Google Scholar
Soriano, A. De, Eiberg, B.A. and Slabnik, E. (1963) Comportamiento de la germinación de semillas de malezas anuales. Revista de Investigaciones Agrícolas 17, 447463.Google Scholar
Thompson, K. and Grime, J.P. (1983) A comparative study of germination responses to diurnally-fluctuating temperatures. Journal of Applied Ecology 20, 141156.CrossRefGoogle Scholar