Observations on chlamydospore production by Fusarium in a two-salt solution

An isolate of Fusarium oxysporum grown in a solution of monobasic potassium phosphate and magnesium sulfate rarely produced chlamydospores. However, when the salt solution was amended with 0.125 mg to 2.0 mg per liter of either glucose or magnesium carbonate, there was an abundant production of chlamydospores within 3 to 4 days after inoculation. While an organic or inorganic source of carbon stimulated chlamydospore formation, repression of chlamydospore production occurred with glucose and magnesium carbonate levels above 2.0 mg per liter. The addition of either an ammonium or nitrate source of nitrogen to the salt solution did not produce additional chlamydospores.