Herbivore impact on trans-seasonal induction of trichome defenses in Solanum carolinense

Open Access
Kolstrom, Rebecca Lauren
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Andrew George Stephenson, Thesis Supervisor
  • James Harold Marden, Honors Advisor
  • Herbivore
  • Induction
  • Defenses
  • Solanum carolinense
Previous studies of the common horsenettle have shown that inbreeding adversely affects resistance to herbivores and compromises the ability of horsenettle to upregulate both chemical and physical defenses in response to herbivory. In this project, inbred and outbred plants from several maternal families were either exposed to herbivory by M. sexta caterpillars (+H) or not exposed to herbivory (-H). Rhizome cuttings from these plants were used to regenerate the plants which were used to test whether herbivory induces physical defenses that persist trans- seasonally. Photographs were taken of close-view leaf cross sections of the regenerated +H and – H plants. Trichomes were counted in each of these photographs. Our results show significant differences between damaged and undamaged progeny with +H progeny exhibiting significantly more trichomes. We also found nearly significant effects of inbreeding on trichome production. These data suggest that damage during one growing season induces defenses that persist into the next growing season. We are currently exploring the effects of parental herbivory on other induced defenses in both inbred and outbred plants.