ENDOPHYTIC FUNGI IN SCOTS PINE NEEDLES - SPATIAL VARIATION AND CONSEQUENCES OF SIMULATED ACID-RAIN

Within- and among-tree variation in assemblages of endophytic fungi in Scots pine (Pinus sylvestris) needles were studied in a subarctic are a where background pollution values are low; the effects of tree densi ty and prolonged simulated acid rain on the occurrence of endophytic f ungi were investigated. The needle endophyte most frequently isolated was Cenangium ferruginosum, accounting for 64% of all fungal individua ls, followed by Cyclaneusma minus (12% of all individuals). Old needle s were colonized more frequently by endophytes than young ones. In you ng needles the colonization by endophytes increased during the summer, whereas in old ones no seasonal variation was detected. Endophyte col onization was positively correlated with stand density and was reduced on pines treated with spring water acidified with either sulphuric ac id alone or in combination with nitric acid. In contrast, nitric acid alone did not affect endophyte colonization.