Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-04T21:09:05.673Z Has data issue: false hasContentIssue false
  • English
  • Français

Environmental factors influencing Pyrenophora semeniperda-caused seed mortality in Bromus tectorum

Published online by Cambridge University Press:  20 November 2012

Heather Finch ,
Phil S. Allen  and
Susan E. Meyer
Heather Finch*
Affiliation:
Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT84602, USA
Phil S. Allen
Affiliation:
Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT84602, USA
Susan E. Meyer
Affiliation:
Rocky Mountain Research Station, Forest Service, United States Department of Agriculture, Shrub Sciences Laboratory, Provo, UT84606, USA
*
*Correspondence E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Temperature and water potential strongly influence seed dormancy status and germination of Bromus tectorum. As seeds of this plant can be killed by the ascomycete fungus Pyrenophora semeniperda, this study was conducted to learn how water potential and temperature influence mortality levels in this pathosystem. Separate experiments were conducted to determine: (1) if P. semeniperda can kill dormant or non-dormant seeds across a range of water potentials (0 to − 2 MPa) at constant temperature (20°C); and (2) how temperature (5–20°C) and duration at reduced water potentials (0–28 days) affect the outcome. When inoculated with the fungus at 20°C, all dormant seeds were killed, but fungal stromata appeared more quickly at higher water potentials. For non-dormant seeds, decreasing water potentials led to reduced germination and greater seed mortality. Results were similar at 10 and 15°C. Incubation at 5°C prevented stromatal development on both non-dormant and dormant seeds regardless of water potential, but when seeds were transferred to 20°C, dormant seeds evidenced high mortality. For non-dormant seeds, exposure to low water potential at 5°C resulted in secondary dormancy and increased seed mortality. Increasing incubation temperature, decreasing water potential and increasing duration at negative water potentials all led to increased mortality for non-dormant seeds. The results are consistent with field observations that pathogen-caused mortality is greatest when dormant seeds imbibe, or when non-dormant seeds experience prolonged or repeated exposure to low water potentials. We propose a conceptual model to explain the annual cycle of interaction in the Bromus tectorum–Pyrenophora semeniperda pathosystem.

Keywords

Bromus tectorumpathosystemPyrenophora semeniperdaseed germinationtemperaturetimewater potential
Type
Research Papers
Information
Seed Science Research , Volume 23 , Issue 1 , March 2013 , pp. 57 - 66
Copyright
Copyright © Cambridge University Press 2012

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

Allen, P. and Meyer, S.E. (2002) Ecology and ecological genetics of seed dormancy in downy brome. Weed Science 50, 241–247.CrossRefGoogle Scholar
Bair, N.B., Meyer, S.E. and Allen, P.S. (2006) A hydrothermal after-ripening time model for seed dormancy loss in Bromus tectorum L. Seed Science Research 16, 17–28.CrossRefGoogle Scholar
Bauer, M.C., Meyer, S.E. and Allen, P.S. (1998) A simulation model to predict seed dormancy loss in the field for Bromus tectorum L. Journal of Experimental Botany 49, 1235–1244.Google Scholar
Beckstead, J., Meyer, S.E., Molder, C.J.andSmith, C. (2007) A race for survival: can Bromus tectorum seeds escape Pyrenophora semeniperda-caused mortality by germinating quickly? Annals of Botany 99, 907–914.CrossRefGoogle ScholarPubMed
Campbell, M.A., Medd, R.W. and Brown, J.F. (1995) Growth and sporulation of Pyrenophora semeniperda in vitro: effects of culture media, temperature and pH. Mycological Research 100, 311–317.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, 155–163.CrossRefGoogle Scholar
Dobson, A. and Crawley, M. (1994) Pathogens and the structure of plant communities. Trends in Ecology and Evolution 9, 393–398.CrossRefGoogle ScholarPubMed
Ji, Y., Zhu, K., Qian, H. and Zhou, H. (2007) Effect of water activity and temperature on growth of Penicillium citreoviride and Penicillium citrinum on MiGao (rice cake). Canadian Journal of Microbiology 53, 231–236.CrossRefGoogle ScholarPubMed
Lahlali, R., Serrhini, M.N. and Jijakli, M.H. (2005) Studying and modeling the combined effect of temperature and water activity on the growth rate of P. expansum. International Journal of Food Microbiology 103, 315–322.CrossRefGoogle ScholarPubMed
Magan, N. and Lacey, J. (1988) Ecological determinants of mould growth in stored grain. International Journal of Food Microbiology 7, 245–256.CrossRefGoogle ScholarPubMed
Marin, S., Sanchis, V., Teixido, A., Saenz, R., Ramos, A.J., Vinas, I. and Magan, N. (1996) Water and temperature relations and microconidial germination of Fusarium moniliforme and Fusarium proliferatum from maize. Canadian Journal of Microbiology 42, 1045–1050.CrossRefGoogle ScholarPubMed
Meyer, S.E. and Allen, P.S. (2009) Predicting seed dormancy loss and germination timing for Bromus tectorum in a semi-arid environment using hydrothermal time models. Seed Science Research 19, 225–239.CrossRefGoogle Scholar
Meyer, S.E., Quinney, D., Nelson, D.L. and Weaver, J. (2007) Impact of the pathogen Pyrenophora semeniperda on Bromus tectorum seed bank dynamics in North American cold deserts. Weed Research 47, 54–62.CrossRefGoogle Scholar
Meyer, S.E., Stewart, T.S. and Clement, S. (2010) The quick and the deadly: growth vs. virulence in a seed bank pathogen. New Phytologist 187, 209–216.CrossRefGoogle Scholar
Michel, B.E. and Kaufmann, M.R. (1972) The osmotic potential of polyethylene glycol 6000. Plant Physiology 51, 914–916.CrossRefGoogle Scholar
Taylor, A.G., Allen, P.S., Bennett, M. and Bradford, K. (1998) Seed enhancements. Seed Science Research 8, 245–256.CrossRefGoogle Scholar