NITROGEN METABOLISM IN ETIOLATED CORN 
SEEDLINGS 1 
By S. L. Jodidi 
Associate Biochemist , Office of Plant Physiological Investigations, Bureau of Plant 
Industry, United States Department of Agriculture 
INTRODUCTION 
The process of seed germination is of great significance as a means 
of attaining deeper and more extensive knowledge concerning the 
physiology of plants. The universal importance of cereals as food 
ana feed has made it desirable to take up a systematic study of these 
plants with the object of throwing additional light on the funda¬ 
mental physiological and biochemical processes involved in the ger¬ 
mination of various cereal seeds. Because of the vast field covered 
by the phenomena in question it was necessary to limit the scope of 
the investigation, and the work has therefore been confined chiefly 
to the study of the nitrogenous compounds (proteins and nonpro¬ 
teins) in cereals. Some interesting studies ( 14 , 16) of these com¬ 
pounds in relation to the nutrition of man and animals have been 
made. 
Before the germination work proper was taken up, preliminary 
experiments showed that wheat (Triticum vulgare) (9 ), 2 oats (Avena 
sativa) (10), corn (Zea mays) (11), and rye (Secale cereale) (12) 
contain polypeptides and free amino acids in their ungerminated 
kernels. 
There is a great deal of information at hand concerning the process 
of germination. In some seedlings the proportions of acid amides 
ana amino acids are fairly uniform at certain stages of germination; 
at other stages the acid amides prevail. Some seedlings, like those 
of grasses and legumes, are rich in asparagine; the seedlings of others, 
like spinach and black radish, are rich in glutamine; and the seed¬ 
lings of still others, like the sunflower and pumpkin, contain both 
asparagine and glutamine, though one of them ordinarily in predomi¬ 
nant proportion (18). As to the interrelationship and significance 
of these facts we do not know much beyond the hypothesis of Schulze., 
that during germination the amino acids are gradually converted 
into asparagine or glutamine (17). 
So far as the occurrence of polypeptides in seedlings is concerned, 
we have no information whatever, nor do we have sufficient knowl¬ 
edge with regard to the humin bodies met with in seedlings. 
It is well known that plant proteins may be split by chemical 
means (acids, alkalies), by bacteria, and by enzymes naturally occur- 
1 Received for publication June 22, 1925; issued December, 1925. Thanks are due to E. H. Toole, of 
the seed-testing laboratory, Bureau of Plant Industry, for valuable suggestions and for assistance with 
materials and apparatus. 
2 Reference is made by number (italic) to “Literature cited,” p. 1163. 
Journal of Agricultural Research, 
Washington, D. C. 
( 1149 ) 
Vol. XXXI, No. 12 
Dec. 15, 1925 
Key No. G-461 
