Embryo and Aleurone Layer of Hordeum. 
833 
Cultures of Endosperms and Inner Endosperms on 
Agar Media. 
It appeared most desirable not to confine this important division of the 
inquiry to one particular type of experimental substratum. 
Experiments were therefore instituted with endosperms and inner 
endosperms upon a 08 % agar medium, this percentage of agar being 
chosen as the result of several preliminary trials, because of the additional 
facilities such a medium might offer in the promotion of the complex 
diffusion processes which present themselves in the type of experiments 
under consideration. 
In the following table are summarized the results of a typical experi¬ 
mental series :— 
TABLE XVII. 
Cultures of Endosperms and Inner Endosperms on o-8% 
Agar with and without Mineral Salts (P 2 ). 
Chilian barley. Culture period, 19 days. Seeds absolute alcohol 72 hours, water 48 hours 
(2 changes). 
Amylase per 20 in :— Reducing sugars 
Exp . 
Objects. 
Medium. 
Medium. Object. 
Total. 
per 20 
in :— 
' equivalent to mg. 
of Cu.) 
Medium. 
Objects. 
1. 
10 endosperms (halved) 
10 inner endosperms (halved) 
Agar-M.S. 
1358 
1707 
3 o6 5 
465 
0-00 
2. 
Agar only 
776 
!552 
2328 
465 
0.00 
3 . 
y 9 yy 
M 35 
232 
1667 
174 
0-00 
Again the fact is evident that the augmentative capacity of the endo¬ 
sperm distinctly surpasses that of the inner endosperm. The results further 
bear evidence that the enzyme generated by the inner endosperm does 
possess a certain capacity for attacking its amyliferous storage reserves ,* 
but this capacity is decidedly inferior to that exhibited by the endosperm, 
as the comparison of Experiments 1 and 2 with Experiment 3 very clearly 
indicates. 
In these experiments examination of the two types of objects at the 
termination of the culture period reveals the same differential features 
as those presented by the gelatine cultures, and their significance does 
not require further detailed reference. 
1 If specimens of barley starch taken from various parts of the inner endosperm are examined 
microscopically, it is invariably found that intermingled with the large fully formed starch grains are 
a considerable number of very minute grains which stain blue on treatment with iodine, and therefore 
consist of starch. It is highly probable that these minute grains are more readily attacked than are 
the larger ones by the amylase of the inner endosperm. These minute grains are probably either of 
the nature of or very similar to ‘ transitory ’ starch. 
Often repeated and searching microscopical examination of specimens of the starch contents from 
inner endosperms after removal from the culture medium in which reducing sugars were demonstrable, 
as in Experiment 3 above, fail to reveal any evidence of visible dissolution of the larger fully formed 
mature starch grains. 
