The effect of fungal endophytes on white spruce trees subject to various physiological stresses.
LE3 .A278 2013
Bachelor of Science
Environmental & Sustainability Studies
Fungal endophytes have the potential to act as an alternative pest control method and research in this area is growing, however the ancillary benefits of fungal endophytes to host plants, especially their influence on stress tolerance in the host, are not well characterized. Chlorophyll fluorescence, specifically the parameter Fv/Fm, can be used to detect stress levels in plants. This study investigated the effects of fungal endophyte inoculation on Fv/Fm values in white spruce (Picea glauca) trees subject to winter, heat, and drought stress. Measurements were taken from May to August, 2012, in Wolfville, Nova Scotia, on 24 white spruce genotypes and three endophyte strains. Endophyte strain did not affect the results, but treatment, date, and spruce genotype often affected Fv/Fm values. Generally, previous studies indicated that endophytes had a positive interaction with their host, often conferring stress tolerance to their host. This was not seen in my study, as endophyte treatment generally played a negative role in the trees, potentially due to the production of reactive oxygen species by endophytes or their damage to the cuticle causing increased minimum leaf conductance, for example. The endophytes did enhance recovery mechanisms to some extent, counteracting some of the negative effects. There appears to be a complex relationship between fungal endophytes and their host, ranging from mutualistic to antagonistic. Additional research into the recovery mechanisms provided by fungal endophytes would help to further our understanding of the interaction between host and endophyte.
The author grants permission to the University Librarian at Acadia University to reproduce, loan or distribute copies of my thesis in microform, paper or electronic formats on a non-profit basis. The author retains the copyright of the thesis.