CRYOPRESERVATION OF SPORES OF VESICULAR ARBUSCULAR MYCORRHIZAL FUNGI

Storage of spores of vesicular‐arbuscular (VA) mycorrhizal fungi in soil at 5 °C is a common way of preserving these fungi. This method was satisfactory for Glomus intraradix Schenck & Smith but not for Gigaspora margarita Becker & Hall, Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe, and Acaulospora longula Spain & Schenck. Preservation of spores at −60 to −70 °C was examined. Cryoprotectants such as DMSO, glycerol, mannitol, and sucrose were ineffective using the freeze‐damage sensitive species G. margarita. Incubation for 47 h in 0.75 to 1.0 M trehalose conferred a measure of freeze damage protection to the spores such that germination rates of previously frozen spores of G. margarita were one tenth to one sixth of controls. The best method of cryoprotection and cryopreservation was found to be slow drying of pot culture soil and freezing the spores in situ. This procedure was satisfactory for the five genera of VA mycorrhizal fungi evaluated. Copyright © 1990, Wiley Blackwell. All rights reserved