Revival of saprotrophic and mycorrhizal basidiomycete cultures after 30 years in cold storage in sterile water.

Vegetatively colonized agar cores of 54 basidiomycete fungal isolates were stored at 5 °C in tubes of sterile distilled water without manipulation for 30 years. The cultures represented 28 isolates of saprotrophic fungi and 26 isolates of mycorrhizal fungi. These cultures came from a group of 57 fungal isolates that were determined to be viable after 20 years of cold-water storage. Overall, 47 of the 54 isolates (87%) grew vigorously when revived after storage for 30 years. Of the 28 saprotrophic fungal isolates, 26 revived (93%); of the 26 mycorrhizal fungal isolates, 21 revived (81%). Eight of 13 isolates (62%) of Laccaria were viable after 30 years, which was considerably less viable than what was found after 20 years for this genus of mycorrhizal fungi. However, a greater percentage of isolates of Laccaria bicolor (83%) were viable than isolates of Laccaria laccata (43%), suggesting that 30 years is approaching the maximum limit for storage in cold sterile water for certain species. Considering the original 135 fungal isolates that were stored in sterile cold water from which this set was derived, overall survival after 30 years of storage was 42%; however, saprotrophic fungi demonstrated considerably greater viability (70%) than mycorrhizal fungi (21%).