ESSENTIAL NONMETALLIC ELEMENTS 



95 



organic phosphates (esters) may also be used as sources of this element. 

 Dox (1911-1912) investigated the assimilation of various phosphorus 

 compounds by Aspergillus niger with the following results: Ortho-, 

 meta-, and pyrophosphates supported excellent growth, as did such 

 organic compounds of phosphorus as phytin, sodium glycerophosphate, 

 sodium nucleinate, casein, and ovovitellin. Sodium hypophosphite 

 (NaH2P02-H20) and sodium phosphite (Na2HP03-5H20) were not 

 utilized and appeared to be toxic. 



Smith (1949) studied the phosphorus metabolism of MeruUus lacrymans 

 and Marasmius chordalis in connection with the utilization of different 

 carbon sources. In glucose medium M. lacrymans grew better when 

 supplied w^ith inorganic phosphate, while M. chordalis grew miore rapidly 

 when supplied with organic phosphorus (adenylic acid). On cellobiose 

 medium M. lacrymans grew faster when supplied with organic phosphorus. 



The role of phosphorus. An idea of the manifold ways in which phos- 

 phorus enters into fungus metabolism may be gained from the studies of 

 Mann (1944, 1944a). Aspergillus niger was grown on a glucose-nitrate 

 medium containing varying amounts of dipotassium orthophosphate. 

 Some of Mann's data on the effect of two concentrations of phosphate are 

 given in Table 17. 



Table 17. The Effect of Two Concentrations of Orthophosphate upon the 

 Appearance, Sporulation, and Other Metabolic Functions of Aspergillus niger 

 (Mann, Biochem. Jour. 38, 1944. Published by permission of the Cambridge 

 University Press.) 



From Table 17 it may be seen that suboptimal amounts of phosphorus 

 affect the metabolism of A. niger in many ways besides diminishing 

 growth. Nitrogen utilization was affected, and the synthesis of three 

 vitamins (thiamine, riboflavin, and nicotinic acid) was greatly decreased. 

 The ability of phosphorus-starved mycelium to utilize oxygen was dimin- 

 ished, as shown by the lower Qo,- Mann also showed that utilization of 



