Scanning Electron Microscopy of Ectomycorrhizae Potential and Limitations

Scanning electron microscopy (SEM) has added considerably to an understanding of the morphology of ectomycorrhizae. Features of the mantle of mature ectomycorrhizae have been studied most frequently. There is considerable variation in arrangement of hyphae and therefore in the appearance of the outer mantle. This variation is due primarily to the fungal symbiont although the host genome may also influence this feature. The Hartig net has been studied from fractured ectomycorrhizal roots and, in the present study, from fractured cryopreserved specimens; general features of the interaction between Hartig net hyphae and contiguous root cells have been described. There are few published accounts of using SEM techniques to study the ontogeny of ectomycorrhizae. This study demonstrates the usefulness of such techniques in studying the initial interaction of hyphae with root hairs and root surfaces, including the extramatrical phase which is normally very difficult to study using other techniques