SPORULATION 



325 



carbon sources for reproduction are Aspergillus niger, glucose, sorbose, 

 sucrose; Glomerella cingidata, sucrose; Phoma betae, sucrose; Monilinia 

 fructicola, sorbose, sucrose; Neocosmopara vasinfecta, maltose, starch, 

 glucose; Pleurage curvicolla, maltose, starch. 



ABC 

 Fig. 66. The effect of three carbon sources and time on the production of perithecia 

 by Melanospora sp. on asparagine medium at 25°C. The carbon sources were: A, 

 glucose; B, sucrose; C, maltose. Above, cultures 11 days old; below, the same cul- 

 tures 22 days old. Note the poor vegetative growth but presence of perithecia on 

 sucrose and maltose, and the abundant early vegetative growth but delayed produc- 

 tion of perithecia on glucose. 



For further information on the effects of nutritional factors on sporula- 

 tion, see Hawker (1950). 



Carbon-nitrogen ratio. It seems to be generally held that a proper 

 balance among the constituents of the medium is quite important in 

 growth and sporulation. Westergaard and Mitchell (1947) investigated, 

 among other factors, the influence of the carbon-nitrogen ratio of the 

 medium on formation of perithecia by Neurospora crassa. Some of their 

 data are given in Table 56. It is evident that high concentrations of 



