OCCURRENCE OF FUNGAL ENDOPHYTES IN TWIGS OF SALIX-FRAGILIS AND QUERCUS-ROBUR

Endophytic fungi of the xylem and bark of Quercus robur and Salix fragilis have been compared to detect interspecific and tissue-specific differences in the communities. Directional influences through compass orientation on species composition have also been investigated in a large mature oak tree. Isolates from Salix were mostly ubiquitous endophytes, with the exception of Phomopsis salicina, whilst those from Quercus appear to be more host-specific. Colonization densities of the most frequently recorded species are comparable, revealing a homogeneous distribution of colonization within the samples. The fungal communities in Q. robur and S. fragilis branches appear to be composed of a small number of dominant species, with little overlap in the species composition of the two communities. Cluster and correspondence analysis indicate that all separate branches are characterized by distinct endophytic communities. Branches of Q. robur taken from different compass directions are colonized mainly by the same endophyte communities, and no directional influence on colonization of Q. robur branches by endophytic fungal communities can be inferred.