Embryo and Aleurone Layer of Hordeum . 819 
As in the case of the embryo, before it is possible to evaluate its 
secretory capacity it is necessary to determine the initial amylase content 
of the aleurone layer directly after its removal from the steeped seed. The 
results of such a determination are given in the following table :— 
TABLE VI. 
Initial Amylase Content of Aleurone Layer of 
Steeped Seed. 
Chilian barley. Seeds 48 hours absolute alcohol, 48 hours water. 
Experiment. 
1. 2.5 aleurone layers 
2 * )) 5 J 
3 * }} }> 
Amylase per 20 aleurone 
layers (equivalent to 
mg. of Cu ). 
506 
675 
675 
Typical examples of the secretory capacity of the aleurone layer are 
given in the following tabulations :— 
TABLE VII. 
Secretion of Amylase by Aleurone Layer. 
Cultures of dorsal aleurone layers (African barley) on liquid and on solid substrata. 
Seeds 24 hours 10 % CuS 0 4 . 
Exp. 
1. 
2. 
3 - 
4 - 
5 - 
6 . 
No. of objects on 
culture medium. 
20 dorsal aleurone layers 
>> n 
>> }> 
99 99 99 
99 99 99 
99 99 99 
Duration of 
culture Medium, 
period. 
2 days 0*55 % asparagin solution 
3 )> )) }> )> 
4 )) >) » 55 
^ >> >) » 
7 if 10 % gel., 0.55 % asparagin-M.S. 
7 ,, 10 % gel.-M.S. 
Amylase per 20 
objects in culture 
medium (equivalent 
to mg. of Cu). 
365 
362 
4 I 4 
269 
852 
55 2 
The above experiments, it is to be noted, were carried out with material 
prepared from seeds sterilized by steeping in copper sulphate solution, 
as will be shown later ; there are certain objections to the use of this reagent 
in the case of aleurone layers, endosperms, and inner endosperms. 
The superior results in Exp. 5 and 6 are not wholly due to prolongation 
of the culture period, but to substitution of a solid for a liquid substratum. 
In the latter circumstances the aleurone layer fragments are apt to be 
drowned, and this seriously interferes with their secretory functions. 
The results comprised in the following table (VIII) may be taken as 
typical examples of the amyloclastic secretory powers of isolated aleurone 
layers prepared from alcohol-water steeped seeds. 
