Date of Award
Spring 6-2-2025
Document Type
Honors Project
University Scholars Director
Dr. Joshua Tom
First Advisor/Committee Member
Dr. Ryan Ferrer
Keywords
Allelopathy, Monoterpenes, Radicle Growth, Lettuce Seeds, Pacific Northwest, Conifers
Abstract
Understanding the allelopathic interactions of native Pacific Northwest conifers, Douglas Fir, Western Hemlock, and Western Red Cedar is crucial to understanding the interactions of each species within their ecological niche. As of now there is little research on allelopathy of PNW conifers, specifically how different damaged states of the conifer tissue could impact the germination rates and radicle growth of a model organism. Analyzing these allelopathic interactions may be crucial to help predict forest regeneration of the PNW in the future. Presented here is the analysis of Douglas Fir, Western Hemlock, and Western Red Cedar tissue that is undamaged, damaged, and water extracted on the germination rate and radicle growth of lettuce seeds. Also, pure Thujone from Western Red Cedar and b-Pinene from Douglas Fir were analyzed as well. The undamaged tissue was found to have no significant interaction on germination or radicle growth. The damaged tissue was found to have a significant distance interaction on both germination and radicle growth. The monoterpene exposure was found to have a significant interaction on germination and radicle growth. Lastly, the water extracts were found to have significant interactions on germination and radicle growth between different concentrations. The severity of allelopathic interactions between the lettuce seeds and the treatments was dependent on the concentration of the treatment and the condition of the treatment tissue. These results provide evidence that these native conifer species might be so dominant due to the unique environment of the PNW facilitating perfect allelopathic interactions with competing species.
Recommended Citation
Mendoza, Lainey E. Ms., "Allelopathy of Western Red Cedar, Douglas Fir, and Western Hemlock on seed germination" (2025). Honors Projects. 236.
https://digitalcommons.spu.edu/honorsprojects/236
Copyright Status
http://rightsstatements.org/vocab/InC/1.0/
Additional Rights Information
Copyright held by author.
Comments
A project submitted for the fulfillment of the requirements for the Bachelor of Arts degree in Honors Liberal Arts.