A comparison of drought tolerance in two conifers with contrasting mycorrhizal associations
Date
2023
Authors
Robson, Bethany
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Drought events are increasing in frequency, severity, and distribution as a result of climate change. Plants have a variety of adaptations to water stress, including symbioses with mycorrhizal fungi. Little is known about how the type of mycorrhizae (arbuscular or ecto-) may affect drought tolerance, especially in conifers that are restricted in what association they can make. Research suggests that there may be an effect of mycorrhizal type on drought tolerance, and that mechanisms for this may be different in arbuscular and ecto- mycorrhizae. The objective of this study was to determine how the type of mycorrhizae may affect drought tolerance in Pinus contorta and Thuja plicata, species that make contrasting mycorrhizal associations. Three experiments were performed using both aeroponics and traditional soil culture to explore the effects of mycorrhizal association on drought tolerance. P. contorta performed consistently better in all experiments when compared to two populations of T. plicata from different ecozones in British Columbia. Quantum yield declined linearly with increasing drought stress in both treatments with mycorrhizal colonization, and non-linearly in the treatment with no colonization. These trends were consistently shown across all seedling populations, which suggests that both types of mycorrhizal symbioses are important in the drought tolerance of these species. Further investigation is needed to determine how mycorrhizae may influence recovery after drought in these species, as well as the mechanisms mycorrhizae may use to improve drought tolerance in host plants like P. contorta and T. plicata.