n8 
Journal of Agricultural Research voi. xxm, No. a 
The results after the first period show the effects upon respiration of 
removing the outer coats 2 and of germination. When the outer coats 
were removed, the results were computed on the basis of calculated dry 
weight after removal of these coats as well as on the basis of the dry 
weight of the intact seeds. Some seeds were discarded during the experi¬ 
ment on account of advancing germination or to leave a convenient num¬ 
ber in a given condition for use in a given apparatus. 
The respiratory quotient was always less than unity, as should be 
expected when the material being respired is fatty or oily, and therefore 
poor in oxygen, as is the case with apple seed. 
Removing the outer coats approximately doubled or trebled the respi¬ 
ratory intensity without altering the respiratory quotient until germi¬ 
nation had well begun. Connected with this increased respiration of the 
seeds was an acceleration of germination, though these seeds were suffi¬ 
ciently after-ripened so that the majority of them germinated in four 
days even in intact condition. 
As germination advanced, the respiratory intensity rapidly increased, 
and in seeds freed from their outer coats the respiratory quotient became 
lower in value. (See last two entries in last column of Table I.) In 
intact seeds at a later stage of germination there is a similar decrease in 
the value of the respiratory quotient, not shown here but illustrated m 
other experiments. 
Godlewski (p), 3 Bonnier and Mangin (4), Gerber ( 8 ), and Ivanoff ( ij) t 
have reported low values for the respiratory quotient of germinating 
oily seeds, or young seedlings. 
According to Godlewski, the respiratory quotient of fatty seeds during 
swelling is a little less than 1.0, but the value of the quotient falls as soon 
as the roots appear and is maintained about constant at from 0.55 to 0.65 
during the period of greatest respiratory intensity, after which it rises 
to about 1.0. His value for the period of greatest intensity is slightly 
lower than the lowest shown in Table I. According to this author, and 
to Gerber, the respiratory quotient of germanating starchy seeds is 
constantly about unity during the entire period of germination. 
* Bonnier and Mangin, however, found that with both oily and starchy 
seeds during germination the respiratory quotient is at first near unity, 
falls gradually to a minimum variable with the species, and then rises 
again to its initial value. In this connection, it should be borne in mind 
that even starchy seeds contain more or less oil. In endospermous, 
starchy seeds, this oil is usually concentrated in the embryo. If, as 
would be expected, this oil is drawn upon very early during germination, 
the large use of oxygen in its conversion into sugars would give a tem¬ 
porarily low value to the respiratory quotient of such seeds, exactly as 
these authors point out in regard to oily seeds. They conclude that, if 
there are characteristic differences in the respiratory activity of the two 
classes of seeds, these differences consist only in the minimum value of 
the respiratory quotient, and not in the fact or direction of its variation 
*The coverings of the mature apple seed consist of: (i) a thick brown, fibrous outer coat with open 
micropyle; (2) a thin, translucent inner coat of very dense structure and without openings, suggesting semi- 
permeable characters; and (3) a delicate, whitish, cellular tissue, somewhat thicker than the inner coat, and 
evidently endospermous. Layer 3 is closely adherent to layer 2, and it is impossible to remove the two 
separately, though the embryo is easily bared by removing the two together. The outer coats constituted 
about 33 per cent, the inner coats and endosperm about n per cent, and the embryos about 56 per cent of the 
wet weight of the seeds. The dry weights of different parts were about 15 per cent, 5 per cent, and 33 per 
cent of the original wet weight of the whole seeds. 
Reference is made by number (italic) to “ Literature cited/* p. 129-130. 
