UBC Theses and Dissertations
Mycorrhizae of outplanted conifer seedlings on eastern Vancouver Island Roth, Aaron Lyle
Mycorrhizal colonization and types of mycorrhizae that formed on container-grown Douglas-fir, western hemlock, and western red cedar seedlings were determined in a nursery near Nanaimo, B.C. and under a range of field conditions on eastern Vancouver Island. Methods included a root clearing, bleaching, and staining procedure that allowed for accurate estimates of percentage colonization and some advantages in mycorrhiza characterization. The percentage of Douglas-fir and western hemlock short roots colonized by ectomycorrhizal fungi in the nursery was highly variable but over 99 percent of the mycorrhizae were formed by Thelephora terrestris. After one field season mycorrhizal colonization levels were between 72 and 93 percent on the new roots formed. The most difficult to regenerate site had the lowest percentage colonization and number of ectomycorrhizal types. T. terrestris mycorrhizae still had the highest relative abundance followed by Rhizopogon vinicolor (on Douglas-fir only), Cenococcum geophilum, Mycelium radicus atrovirens, Tujber-like, Sndogone-like, and 38 minor types of ectomycorrhizae. Some types of ectomycorrhizae were only present or common on specific sites. This included a type that formed spore-like structures on the mantle cystidia and a type that produced red-brown hyphal exudates. Douglas-fir seedlings artificially inoculated with R. vinicolor in an Oregon nursery were taller than control seedlings when outplanted but no height or weight difference was found after one field season. The 17 types of mycorrhizae that formed on the control seedlings were dominated in relative abundance by a type that was morphologically identical to that formed on the seedlings that were artificially inoculated with R. vinicolor. Western red cedar did not form mycorrhizae in the nursery but formed low levels of vesicular-arbuscular mycorrhizae in the field that included both fine and coarse endophytes.
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