BULEE TIN: OF THE 
;USDEPARTMENT OFAGRICULTURE 
No. 183 
Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief. 
April 13, 1915. 
(PROFESSIONAL PAPER.) 
MORPHOLOGY OF THE BARLEY GRAIN WITH REFERENCE 
TO ITS ENZYM-SECRETING AREAS. 
By Arzert Mann, Plant Morphologist, Office of Agricultural Technology, and EE Vis 
Harwan, Agronomist in Charge of Barley Investigations, O,ffice of Cereal. Investiga- 
tions. 
CONTENTS. 
Page. Page. 
introduc tionmessssn sees kewcctcssseeca see es 1 | Source of cytatie and proteolytic ferments...- 18 
Structure/of the barley. grain 23.22. s252i<22 22 2 |. Function of the aleurone layer ..... .«---<8-* 18 
Development of the barley grain...........-- 5 | Greater diastatic power of small-berried-and 
Germinajtionias vaste ees sa nea Susu 8 of high-nitrogen barleys...-.-.---..-------- 19 
Conversion of.the endosperm.........-:.----- On| Met CIENCY OMCONVErSIONS ease. =e see sacle 21 
Résumé of the conclusions of other investi- American barley ssiesase sje ollie ecisieee a 27 
PAL ONS tama Naeem Sse Ne Ra 10 | Modifications possible by culture.........--- 28 
Source of diastatic ferments..............--- 12 | Foreign barleys......-.----- stan sh eeeoaaas 30 
Location of dizstase secretion .......--..---- LMS SUM Any Saw aso vale see seraene miarecne Ace alelelers 31 
INTRODUCTION. 
The value of the barley crop to the American farmer depends upon 
two factors, the yield per acre and the price per bushel. An increase 
of revenue is as readily effected by one as by the other. The yield is 
necessarily an agricultural problem; the price is also, within certain 
limits. Although the daily price of any market product ordinarily 
varies over a considerable range, higher values are placed upon those 
offerings which most perfectly meet the requirements of consumers. 
A superior quality is the equivalent of a greater quantity. The nearer 
a farmer can come to producing a product ideally suited to its uses, 
the higher will be the price which he will be able to command. 
By far the greatest demand upon the barley crop is for the purpose 
of malting. This operation consists essentially in the breaking down 
of the cell walls of the endosperm of the barley grain so as to leave its 
starch grains exposed to later enzymatic actions, and also in the 
abundant production of these enzyms, both the diastatic and pro- 
teolytic. The abundant formation of diastase has long been con- 
Nortg.—This paper is intended for distribution to agronomists, station directors, brewery chemists, and 
selected maltsters. 
75719°—Bull. 183 —15——1 
