THE OCCURRENCE OF ENDOPHYTIC FUNGI IN DOUGLAS-FIR SEEDLINGS AND SEED

Abstract

Segments taken from the roots and shoots of healthy 1-year-old seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) collected over a 2-year period from two British Columbia forest nurseries, were surface-sterilized, and incubated on various media. Fungi grew from segments of over 80% of the seedlings, the most frequent being Fusarium oxysporum Schlecht., F. redolens Wr., Mycelium radicis atrovirens, Cylindrocarpon didymum (Hart.) Wollenw., and C. radicicola Wollenw. Fungi were isolated more frequently from the shoot than from the root segments. Isolations from segments with the bark intact were more frequent than from segments that had the bark removed. Seedlings collected in the winter produced more fungi than those collected during the summer. Segments from diseased seedlings and seedlings grown under sterile conditions produced mycofloras which were different from each other and from that of healthy nursery-grown seedlings. Without exception, fungi grew from surface-sterilized seed placed on malt agar and samples from different seedlots had different floras. Stained sections clearly showed hyphae and chlamydospores well within the tissue of roots, shoots, and seed coat.