On the mechanism of the biological action of some nitrophenols

The pH dependence of the germinative capacity inhibition by 14 nitrophenol derivatives was estimated on the conidia ofNeurospora sitophila. The improtance of maintaining accurate pH during biological tests, particularly with derivatives possessing a low pK value is emphasized. The McGowan relationship cannot be applied to the group of substances investigated here. No relationship could be established between the biological activity and lipid solubility. The effect of acidity of the medium and pK of fungicides on the course of absorption of phenols byNeurospora sitophila spores was studied.