pH AND GROWTH 



155 



requires the more expensive and elaborate apparatus. The colori- 

 metric method yields approximate measurements that can be 

 simply and quickly achieved. The electrometric method depends 

 upon the ability of solutions of acids, bases, and salts to conduct 

 an electrical current, differences being attributable to concentra- 

 tion; the colorimetric method involves changes in the colors of 

 indicators, each within a given range of pH, and the matchino- 

 of colors with standards. 



pH and growth. Hydrogen-ion concentration does not equally 

 influence all the vital processes or activities of fungi, as might be 

 anticipated. Much of what has been learned about the effects 

 of pH and pOH on fungi has come from studies on the influence 

 of reaction upon growth rather than upon individual processes, 



TABLE 12 



Range of Hydrogen-Ion Concentration Permitting Growth of Various 



Fungi 



Authority 



Sherwood (1923) 

 Herrick (1939) 

 Johnson (1923) 

 Johnson (1923) 

 Johnson (1923) 

 Johnson (1923) 

 Johnson (1923) 

 Johnson (1923) 

 Meacham (1918) 

 Meacham (1918) 

 Meacham (1918) 

 Meacham (1918) 

 Webb (1919) 

 Webb (1919) 

 Webb (1919) 

 Webb (1919) 

 Jackson (1940) 

 Jackson (1940) 

 Wolpert (1924) 

 Wolpert (1924) 

 Wolpert (1924) 

 Wolpert (1924) 

 Wolpert (1924) 

 Wolpert (1924) 

 Wolpert (1924) 

 Wolpert (1924) 



Organism 



Fusarium lycopersici 

 St ere um gausapatum 

 Mucor glomerula 

 Fusarium bullatum 

 Aspergillus oryzae 

 Aspergillus terricola 

 Penicillium i tali cum 

 Penicillium var labile 

 Lenzites saepiaria 

 Fomes roseus 

 Merulius lacrymans 

 Coniophora cerebella 

 Lenzites saepiaria 

 Aspergillus niger 

 Penicillium cyclopium 

 Botrytis cinerea 

 Pythium sp. 

 Rhizoctonia solani 

 Lenzites saepiaria 

 Daedalea confragosa 

 Polystictus versicolor 

 Ar miliaria me lie a 

 Pholiota adiposa 

 Polyporus adustus 

 Pleurotus ostreatus 

 Schizophyllum commune 



Range within Which Growth 

 Occurred 



2.8 and 8.4 

 2.0 and 8.2 

 3.2-3.4 and 8.7-9.2 

 2.3-2.2 and 9.2-11.2 

 1.6-1.8 and 9.0-9.3 

 1.6-1.8 and 9.0-9.3 

 1.9-2.2 and 9. 1-9.3 

 1.6-1.8 and 10.1-11.1 



1.9 (optimum, 3.0) 

 1.9 (optimum, 3.0) 

 1.0 (optimum, 3.0) 

 1.9 (optimum, 3.0) 

 Below 2.8 and 7.4 



2.8 and 7.4-8.8 



Below 2.8 and approximately 9.6 

 Below 2.8 and 7.4 

 2.5-3.5 and 8.5 

 2.5 and 7.5-8.5 



3.4 and 7.3 



3.5 and 7.2 

 2.5 and 7.6 



2.9 and 7.4 

 2.8 and 7.0 

 3 . 5 and 7 . 6 

 3.0 and 7.5 

 3.4 and 7.0 



