SPORE METABOLISM 393 



Table 1. Chemical Changes during Germination of Uredospores 

 of Puccinia graminis tritici* 



Amount, Per Cent of Dry Weight 



lipid fraction. The conidia of Erysiphe graminis, like the rust spores 

 of Table 1, appear to be relatively high in fat (310). 



During the germination of spores of Aspergillus nidulans, the most 

 pronounced changes which occur in the first few hours are: decline in 

 polymetaphosphate and in organically bound phosphate, disappearance 

 of part of the free amino acids of the spore, and a progressive fall in 

 total lipid (253). 



Several hydrolytic enzymes — acting on starch, oligosaccharides, glu- 

 cosides, pectic substances, proteins, and urea — occur in crude spore 

 preparations; the early literature is reviewed by Mandels and Norton 

 (195). Spores of Myrothecium verrucaria have been found to possess 

 an enzymatic system acting on ascorbic acid (185, 186), another system 

 oxidizing sulfhydryl compounds to disulfides (191), and one or possibly 

 two enzymes acting on sucrose (184, 187, 188). The invertase of M. 

 verrucaria is synthesized rapidly during germination and appears in 

 the medium almost immediately (190). These enzymes are inactivated 

 by an acid treatment which does not kill the spore or damage its res- 

 piration; from this fact it has been proposed that they are located at or 

 near the spore surface (184, 185). The diphosphopyridine nucleotidase 

 of Neurospora crassa is produced primarily or entirely by the conidia 

 and is so easily washed out of the cell that it, too, may have a surface 

 location (309). 



Although there is as yet no reason to think that spore respiration dif- 

 fers fundamentally from that of mycelium, studies of the general prob- 

 lem should contribute to our understanding of both spore germination 

 and fungicidal action. Data available at present are too fragmentary 

 to support any firm theoretical structure or even generalized descrip- 

 tion; the work summarized here should not therefore be taken as nec- 

 essarily applying to all fungi. 



The endogenous respiration of ascospores of Neurospora tetrasperma 

 is shown in Figure 2. The curve has an upward break coincident with 



