Isolation of Mycorrhizal Fungi From Roots of Individual Slash Pines

The isolation of fungal symbionts from mycorrhizae of individual slash pines is described. Root material was taken from 30, 4-year-old wildlings growing in openings within a 20-year-old plantation of the same species located in the Upper Coastal Plain region of Georgia. Solutions of both NaClO and HgCl2 were employed for surface sterilization; 100 ppm HgCl2 for 4 minutes gave best results. A total of 1600 mycorrhizae were plated on nutrient agar. Of these, 213, or 13.3 percent, yielded pure cultures of fungal symbionts. Three different fungi were isolated from 1 mycorrhiza and 2 from each of 7 other mycorrhizae. The 222 separate isolates included 4 of Cenococcum graniforme (Sow.) Ferd. and Winge and 218 basidiomycetous isolates. The latter were arbitrarily divided into 22 different species groups based on cultural characteristics. More than 1 fungal symbiont was found associated with the roots of most trees. Roots of one tree yielded 7 different mycorrhizal fungi.