Germination of Chlamydospores of Three Glomus Species as Affected by Soil Matric Potential and Fungal Contamination

ABSTRACT

Chlamydospores of Glomus darum, G. etunicatum, and G. macrocarpum were placed on filter membranes and buried in pasteurized or nonpasteurized soils having matric potentials of -10, -100, -1000, and -10,000 mbar. Membranes were removed from soil following a 2-wk incubation, and the percentages of chlamydospores germinated and contaminated by other fungi were determined. For the three species, maximum germination occurred at a matric potential of -100 mbar. Soil pasteurization did not affect germination significantly. The number of chlamydospores with contaminating fungi was not influenced by soil pasteurization. Contamination was low at -10 mbar, but a high percentage of chlamydospores were contaminated in drier soil. The abundance of contaminating fungi was correlated negatively with chlamydospore germination under some conditions. Contaminating fungi were species of Fusarium, Penicillium, Trichoderma, and Chaetomium which were apparently introduced with the chlamydospores.

Key Words:

• vesicular-arbuscular mycorrhizae
• soil pasteurization
• hyperparasites
• Glomus