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 sporangio-spores and chlamydo-spores 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 thebest C-sources whereas, inositol was the inferior one. The optimum temperature for growth and spore production was ranged between 28-31°C. 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. |
