Diverting Resources to Turn on Resistance: Influences of Biotic and Abiotic Stresses on Aspen Seedlings

• Author / Creator

  Najar, Ahmed

• The interactions between biotic and abiotic stresses and their influence on plant reserves in non-photosynthetic tissues (i.e., roots and stems) and the role of plant reserves in tree defenses are poorly understood. Aspen seedlings grown under different conditions (light, fertilizer) were grouped in three groups based on their nutrient and carbohydrate reserves. After dormancy, half of the seedlings in each group were subjected to feeding by forest tent caterpillar (Malacosoma disstria). We analyzed foliar and reserve chemistry and explained their effects on plant defenses and larval performance. We found that reserve TNC and nutrients can affect foliar TNC, Nitrogen, Carbon/Nitrogen ratio, defense chemistry, and the overall plant response to herbivory. Seedlings with high carbohydrate-to-nutrient reserve ratio had the greatest induction of defensive compounds and sustained the lowest insect damage. This study highlights the importance of plant defenses mediating the intricate relationship between plants and herbivores.

• Subjects / Keywords

  • Aspen reserves
  • Populus-tremuloides
  • Defoliator deterrence
  • Carbon nutrient balance hypothesis
  • Phenolic glycosides
  • Malacosoma disstria
  • Growth differentiation balance hypothesis
  • Plant defense theories

• Graduation date

  Fall 2012

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3Q927

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.