Effect of CO₂ on the germination of conidiospores of Aspergillus niger

Abstract

The effect of different concentrations of CO₂ on the germination of conidiospores of Aspergillus niger A₅ has been studied using Pardee's buffer mixtures which maintain constant CO₂ tensions. The beneficial effect of CO₂ on germination is maximum at 0.5% CO₂ concentration, when 70-90% of the spores germinate within 6 hours, whereas in controls with air containing 0.03% CO₂ there is only 15-20% germination at 6 hours. At higher CO₂ concentrations this beneficial effect of CO₂ on germination diminishes and at 3% there is a complete inhibition of spore germination. The spore density and the ph of the medium have a noticeable effect on germination rates in presence of 0.5% CO₂. The germination rates decrease at spore densities higher than 5·10⁵/ml and at a ph of 6.8.