PLANT WORLD FOR AUGUST, 1019, WAS ISSUED FEBRUARY 4, 1920 



WATER CONTENT AND TEMPERATURE AS FACTORS 

 INFLUENCING DIASTASE FORMATION 

 IN THE BARLEY GRAIN 



WILLIAM EUGENE PICKLER 



Wabash College, Craivfordsville, Indiana 



1. INTRODUCTION 



The hydrolysis of starch-paste by germinating barley was ob- 

 served by Kirchoff in 1814. The first account of an enzyme in 

 solution is that of Dubrunfaut (1830). He found that an aque- 

 ous extract of malt converted starch-paste to sugar. The active 

 agent for this conversion was not discovered until 1833. In 

 that year Payen and Persoz (1833) precipitated by means of 

 alcohol, from an aqueous extract of malt, a white powder which 

 had the power of converting starch paste to sugar. This powder 

 they called diastase. Since its discovery our knowledge of dias- 

 tase has greatly increased. Its formation, distribution, and be- 

 havior to temperature, chemical agents, etc., have been the sub- 

 ject of especial investigations, and excellent discussions of the 

 literature may be found in Green (1901), Effront (1902) and 

 Czapek (1913). 



Comparatively little is known concerning the relative activity 

 of diastase, its increase or its decrease, in the resting seed under 

 different conditions of moisture, temperature, etc., in storage. 

 Since the quantity of water in the seed varies considerably under 

 different conditions of storage and relatively small variations 

 have a marked effect on fundamental life processes, as for ex- 

 ample, respiration, it was thought worth while to investigate the 

 effects of moisture and temperature on the grain in storage. 

 White (1909) in studying the latent life of resting seeds, found 

 that active diastase is present in them in an appreciable amount. 

 The diastase and other enzymes 



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THE PLANT WORLD, VOL. 22, NO. 8 

 AUGUST, 1919 



