BioQUEST Curriculum Consortium Botanical Society of America Southeast Missouri State University Missouri Botanical Garden
A Model of Factors Related to Tradeoffs in Cyanogenesis and Seed Production in Trifolium repens
Authors          Audiences          Overview           Materials          Resources           Future Directions



Joyce Cadwallader
Saint-Mary-of-the-Woods College

Mary Puterbaugh Mulcahy
University of Pittsburgh at Bradford

Tammy Tintjer
Saint-Mary-of-the-Woods College


Possible Audiences:

Undergraduates in ecology and related courses  


Brief Overview:

Our group was intrigued by the factors which might be affecting the frequency of cyanogenesis in Trifolium repens after hearing the presentation of Dr. Kenneth Olsen (a.k.a., Dr. Cyanide) and reading his paper on the topic. We built a model incorporating some of the factors mentioned in Dr. Olsenís paper (Olsen, 2007) to demonstrate the effects in a population of organisms with varying characteristics. The factors were frequencies of the two alleles of the two genes that control cyanogenesis, different levels of predation, and energy used for maintenance, reproduction and cost of the defense alleles. The two genes interact to produce cyanogenesis, the Ac/ac which encodes for the production of the cyanogenetic glucosides and the Li/li which encodes the information for the production of the hydrolytic enzyme, linamarase. Both genes exhibit Mendelian dominance and need to be present for cyanide production in the plants.  


Project Materials:

Word Document with the text from the poster Excel sheet containing the model Word Document with the table and figure from our poster Word Document with the screen shot of the spreadsheet with some annotation.  


Resources and References:

J. J. Burdon. (1983) Biological Flora of the British Isles. Trifolium repens. Journal of Ecology, 71,307-330. This is a review paper on clover with a lot of interesting ecological information on both cyanogenesis and chevron patterns as related to herbivory and other factors. Phyllis D. Coley, John P. Bryant, and F. Stuart Chapin, III. (1985) Resource Availability and Plant Antiherivore Defense. Science, 230, 895-899. This is a paper proposing a theory that allocation to defenses in plants in related to the resource availability in an environment. K. M. Olsen, B. L. Sutherland, and L. L. Small. (2007) Molecular evolution of the Li/li chemical defence polymorphism in white clover (Trifolium repens L.) Molecular Ecology, 16, 4180-4193. This paper describes the Ac and Li alleles that affect cyanogenesis in clover.  


Future Directions:

Determine if different results could be obtained if we set the cost of the defense alleles lower and/or if we set the cost of herbivory higher. Gather data from the field to aid in generating better values to use in our model.  



- Poster.doc
- resource_model.xls
- figures.doc
- screen_shot of model.doc