20 NUTRITION OF FUNGI 



sole source of carbon with their growth on media containing 

 both citrates and dextrose. The organisms tested included those 

 commonly associated with the decay of citrus, namely Penicillium 

 digitatum, P. stoloniferuvi, Diplodia natalensis, Phomopsis citri, 

 Alternaria citri, Oospora citri-aurantii, and Sclerotinia libertiana. 

 All of them were able to grow in orange juice (pH 3.8), but only 

 P. stoloniferum, O. citri-aurantii, and 5. libertiana achieved a fair 

 amount of growth on lemon juice (pH 2.5). None of these fungi 

 grew luxuriantly when citrate was the sole source of carbon. 

 After P. stoloniferum and 5. libertiana had been started in dextrose, 

 they could, if transferred to media containing citric acid, achieve 

 fairly good growth. In general, these organisms attained better 

 growth in the solutions containing citrate plus dextrose than in 

 dextrose alone, only Penicillium digitatum and Phomopsis citri 

 being unable to utilize citrate as a supplement. 



Leptomitns lacteus and Apodachlya brachyneina utilized all 

 the straight carbon-chain fatty acids up to and including capric 

 acid, with the exception of formic acid and propionic acid 

 [Schade (1940)]. 



A very different approach to the problem of utilization of or- 

 ganic compounds was made by Tamiya (1932), who attempted 

 to determine the relationship of chemical structure to assimilabil- 

 ity. For this purpose he employed 123 organic compounds with 

 Aspergillus oryzae as the test fungus and noted whether the com- 

 pounds were favorable for spore germination, were suitable for 

 subsequent growth, and were utilized in respiration. Of those he 

 studied, only 51 were found suitable to promote mycelial growth 

 and were respired by A. oryzae; 8 others were used in respiration 

 although they did not support growth. Tamiya concluded that 

 the carbohydrates and polyatomic alcohols constitute the best 

 sources of carbon. 



The aromatic series of alcohols and the monoatomic alcohols 

 of the aliphatic scries, with the exception of ethyl alcohol, were 

 not utilized. Aldehydes, ketones, and esters were unsuitable. 

 Citric, lactic, malic, pyruvic, and succinic acids were among those 

 utilized. Tamiya concluded that only those compounds are as- 

 similated which possess certain characteristic atomic groups that 

 he called "chief radicals." These chief radicals must be joined 

 either in a ring or straight chain to "residual radicals"; and the 



