1162 Stozvard.—Amy loci as tic Secretory Capacities of the 
VIII. The Influence of Various Carbohydrates on the Secre¬ 
tion of Amylase by the Embryo and Aleurone Layer. 
The relative nutrient value to the embryo of certain carbohydrates was 
investigated by Brown and Morris (loc. cit., p. 483). As a source of readily 
assimilable carbon they found cane sugar to have the highest value of 
any of the various sugars examined. The important and interesting fact 
was also elicited that this carbohydrate inhibits the amyloclastic secretionary 
function of the columnar epithelial cells. 
When, for example, cane sugar was included in the starch-gelatine 
culture medium used by these authors, upon which embryos alone were 
placed, or when embryos with the proximal halves of their endosperms 
attached were planted in loosely packed glass wool saturated with 3-5 % cane 
sugar solution, no obvious signs of disintegration of starch granules were 
evident. This phenomenon, they state, is not due to inactivation of the 
secreted amylase (diastase) by the sugar present, but to the fact that ‘ under 
these particular conditions the epithelial cells of the scutellum do not secrete 
any amylo-hydrolytic enzyme \ The secretion of active amylase by the 
columnar epithelium, they conclude, is to be regarded to some extent as 
a starvation phenomenon. 1 
The observations of Brown and Morris regarding the selective exercise 
by the embryo of its secretory functions is probably a widespread pheno¬ 
menon. The secretion of various enzymes, more especially amylase, by 
different Bacteria and Fungi, as shown by the researches of Wortmann, 2 
Duclaux, 3 Busgen, 4 Fermi, 5 Pfeffer, 6 Katz, 7 and Saito, 8 is influenced by the 
composition and constitution of the nutrient or experimental substrate. 
In view of the important aspect of the regulative control which the 
embryo exercises over the secretory functions of the scutellum a number of 
culture experiments were carried out with sterilized embryos on media 
(liquid and semi-solid) containing either cane sugar, invert sugar, or 
dextrose, with the express object of studying the influence which each of 
1 Quite recently Wohl and Glimm (Biochem. Zeitschr., xxvii, 1910, pp. 349-75), in an in¬ 
vestigation of the extent to which the saccharification of starch paste by amylase is inhibited by 
addition of various sugars, find that cane sugar in 20 % concentration does not produce any 
inhibition. 
The above statement of Brown and Morris is, therefore, well founded; the epithelial cells 
under the conditions cited and under my own experimental conditions do not exercise their secretory 
functions. 
2 Wortmann : Botan. Zeitung, 1890, p. 581; Zeitschr. f. physiol. Chem., vi, 1882, 
pp. 287-329. 
3 Duclaux : Chimie biologique, pp. 193, 195, and 210. 
4 Busgen : Ber. d. Deutsch. Botan. Gesellsch., Bd. cxi. 
5 Fermi : Centralbl. f. Bakt. 11. Parasitenkunde, x, pp. 401-8. 
6 Pfeffer: Pflanzenphysiologie, Bd. i, 1897, pp. 361, 506. 
7 Katz : Jahrb. f. wiss. Botanik, xxi, 1898, pp. 599-618. 
8 Saito : Wochenschr. f. Brauerei, xxvii, 16, 1910, p. 181. 
