Structure of ectomycorrhizae formed by Wilcoxina mikolae var. mikolae with Picea mariana and Betula alleghaniensis
The structure of ectomycorrhizae synthesized between the E-strain fungus, Wilcoxina mikolae var. mikolae and two tree species, Picea mariana and Betula alleghaniensis, was characterized by light microscopy and scanning electron microscopy. For both mycorrhizal types, mantle formation was visible on lateral roots within 10 days of inoculation. Picea mariana ectomycorrhizae had a very thin mantle whereas B. alleghaniensis ectomycorrhizae had a mantle consisting of several layers. For both mycorrhizal types, the innermost mantle hyphae were embedded in a considerable amount of mucigel on the root surface. A well-developed Hartig net with labyrinthic growth occurred in both types of mycorrhizae. Betula alleghaniensis ectomycorrhizae had a paraepidermal Hartig net, and the root epidermal cells were radially elongate at an oblique angle. The Hartig net of P. mariana ectomycorrhizae penetrated the epidermis and all layers of the cortex. The cytoplasmic density of the intercellular hyphae was greatest towards the root apex. Ectomycorrhizal associations formed by E-strain fungi were similar to ectomycorrhizae formed by other fungi. Key words: E-strain, ectomycorrhizae, Wilcoxina, Picea, Betula, Hartig net.