A Race for Survival: Can Bromus tectorum Seeds Escape Pyrenophora semeniperda-caused Mortality by Germinating Quickly?
Authors: Beckstead, Julie; Meyer, Susan E.; Molder, Cherrilyn J.; Smith, Caitlyn
Source: Annals of Botany, Volume 99, Number 5, May 2007 , pp. 907-914(8)
Publisher: Oxford University Press
Abstract:
<sec><st>Background and Aims</st> Pathogen-seed interactions may involve a race for seed resources, so that seeds that germinate more quickly, mobilizing reserves, will be more likely to escape seed death than slow-germinating seeds. This race-for-survival hypothesis was tested for the North American seed pathogen Pyrenophora semeniperda on seeds of the annual grass Bromus tectorum, an invasive plant in North America. In this species, the seed germination rate varies as a function of dormancy status; dormant seeds germinate slowly if at all, whereas non-dormant seeds germinate quickly. </sec> <sec><st>Methods</st> Three experimental approaches were utilized: (a) artificial inoculations of mature seeds that varied in primary dormancy status and wounding treatment; (b) naturally inoculated undispersed seeds that varied in primary dormancy status; and (c) naturally inoculated seeds from the carry-over seed bank that varied in degree of secondary dormancy, habitat of origin and seed age. </sec> <sec><st>Key Results</st> In all three approaches, seeds that germinated slowly were usually killed by the pathogen, whereas seeds that germinated quickly frequently escaped. Pyrenophora semeniperda reduced B. tectorum seed banks. Populations in drier habitats sustained 50 times more seed mortality than a population in a mesic habitat. Older carry-over seeds experienced 30 % more mortality than younger seeds. </sec> <sec><st>Conclusions</st> Given the dramatic levels of seed death and the ability of this pathogen to reduce seed carry-over, it is intriguing to consider whether P. semeniperda could be used to control B. tectorum through direct reduction of its seed bank. </sec>Keywords: Biocontrol; biotic resistance; cheatgrass; Drechslera campanulata; invasive species; mycoherbicide; pathogen; seed bank; seed-borne
Document Type: Research article
DOI: http://dx.doi.org/10.1093/aob/mcm028
Publication date: 2007-05-01
- Annals of Botany is an international plant science journal with editorial offices in Australia, China, Japan, Mainland Europe, UK and USA. It is published monthly in both electronic and printed forms with at least one extra issue each year that focuses on a particular theme in plant biology. The Journal is managed by the Annals of Botany Company, a not-for-profit educational charity established to promote plant science worldwide.
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- In this Subject: Botany
- By this author: Beckstead, Julie ; Meyer, Susan E. ; Molder, Cherrilyn J. ; Smith, Caitlyn

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