Best nutritional, physiological and environmental conditions favored growth and sporiolation of VAM fungi. Bushnell’s medium was the superior one for growth and production of sporangiospores and chlamydospores of VAM isolates. The organic N was better than the inorganic N sources while urea and NaNO2 were not suitable for growth and sporulation. Glucose (for mycelial dry weight) and sucrose (for spore production) were the best C-sources whereas, inositol was the inferior one. The optimum temperature for growth and spore production was ranged between 28-31C. The optimum pH for growth and sporulation was lower in VAM-B (pH 7.0) than other VAM isolates (pH 7.6-8.0). VAM growth and sporulation decreased sharply as relative humidity increased from 14 to 100%. The mycelial dry weight and sporulation of the VAM isolates was affected differently under diffused, yellow, red, green, blue lights and darkness conditions.
Key words: Vesicular arbuscular fungi, VAM fungi, axcenic cultures, nutritive media, nitrogen sources, carbon sources, temperature, relative humidity and light waves.
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