Arum-type of arbuscular mycorrhizae, dark septate endophytes and Olpidium spp.
in fine roots of container-grown seedlings of Sorbus torminalis (Rosaceae)
The aim of this study was to determine the mycorrhizal status of nursery
seedlings of the wild service tree (Sorbus torminalis), which belongs to the
Rosaceae family. Its mycorrhizal associations are still fragmentarily known,
and data from the few existing studies indicate that it forms ectomycorrhizal
symbiosis (ECM). We analyzed the degree of mycorrhizal colonization of thirty
2-year-old container-grown S. torminalis nursery seedlings, which belonged to
three single-tree progenies. The roots were dominated by arbuscular
mycorrhizae (AM), with the morphology of the Arum-type containing arbuscules,
vesicles and hyphae; however, no ECM structures were found. The degree of root
colonization of the analyzed seedlings by AM fungi was 83.6% and did not
differ significantly between the three single-tree progenies. In addition to
AM, structures of dark septate endophytes (0.7%) and sporangia of Olpidium
spp. (1.1%) were found in wild service tree roots. In agreement with previous
studies, we confirmed arbuscular mycorrhizae for S. torminalis. Moreover, this
is the first report that roots of this Sorbus species show the Arum-type
morphology of AM and are associated with Olpidium species