VIEW ARTICLE

Interaction of pH and Temperature with Exogenous Carbon and Nitrogen Nutrition in Conidial Germination by Aspergillus flavus. T. Pass, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061, Present address of senior author: Department of Biology, Morehead State University, Morehead, Ky. 40351; G. J. Griffin, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061. Phytopathology 64:1151-1152. DOI: 10.1094/Phyto-64-1151.

Maximum germination by Aspergillus flavus conidia occurred at 35 C in two axenic nutritional systems. However, the rate of germination in glucose plus amino acid nitrogen, supplied as peptone, was much more rapid than in glucose plus ammonium nitrogen. Percentage germination at reduced temp (25 C) in glucose plus peptone was more than double that in glucose plus ammonium. Using both citrate-phosphate and phosphate buffers, a broad pH optimum range (pH 3.0 - 7.5) for germination was observed in glucose plus peptone, while a narrower optimum range (pH 4.5 - 6.0) was observed in glucose plus ammonium. Low soil temp and high soil pH may restrict A. flavus conidial germination less in soil environments where amino acid nitrogen is the principal nitrogen source.