A PROCEDURE FOR ISOLATION OF SINGLE‐SPORE CULTURES OF CERTAIN ENDOMYCORRHIZAL FUNGI

Abstract

SummaryA procedure for the isolation of single‐spore cultures of endomycorrhizal fungi is described. A single spore is placed on plant roots with a Pasteur pipette by use of a binocular microscope, and the plant is transplanted into sand in a 50 ml growth tube. Plants are incubated for 6 to 8 weeks in a greenhouse and are continuously subirrigated by capillarity with dilute (5 to 10%) Hoagland's solution. Forty to 80% of plants inoculated by this technique with single spores of Glomus macrocarpus, G. etunicatus and G. caledonius became infected. Cultures of G. constrictus and G. microcarpus were not obtained. Hoagland's solutions of up to 25% were equally effective for isolating G. macrocarpus, but limiting plant size by using only 5 or 10% Hoagland's solution was advantageous. The presence of spores on living root systems was the most reliable indicator of fungal development. Non‐inoculated control plants incubated in a common Hoagland's solution reservoir with inoculated plants never became mycorrhizal. The procedure uses readily available materials, is easy to use in the laboratory and conserves greenhouse space and labour.