A comparative study of endophytic mycobiota in leaves of Acer saccharum in eastern North America

Endophytic fungal flora of the symptomless lamina and petiole of Acer saccharum have been compared to detect inter-sites and tissue-specific differences in the communities from two native and one urban stands. Twenty seven different fungal taxa were isolated, but only 19 endophytes were present in frequencies of colonization higher than 1 %. Although the species composition overlaps within sites, all of these species were found in an old-growth forest (300 years old), but only 18 (67 %) in a regenerated (managed) forest (80 year old) and 8 (30 %) in an urban plantation. Both, the numbers of species and fungal isolation frequency, were significantly higher for leaves than for petioles, showing an organ and segment-specific distribution. The gradually increasing of the presence of dark mycelia from native forests to urban plantation was discussed on the basis of the presumably impacts of the temperature and light following the 1998 ice-storm in Quebec, Canada.