THE TRANSLOCATION OF THE FOOD MATERIALS OF 
THE WHEAT SEEDLING 1 
By L. Edwin Yocum, 2 
Iowa Agricultural Experiment Station 
INTRODUCTION 
At no time in the life history of the plant are the changes due to 
metabolism proportionally as great as in the seedling stage, when the 
reserve food of the kernel is changed into simpler and more Soluble 
products and then used as a source of energy or as a part of the young 
plant. Many of the steps of anabolism and katabolism are poorly 
understood. Spoehr (37 ) : gives a good summary of our present 
knowledge on this point. 
It is the aim of this work to show the chemical and physical changes 
which take place during the germination of wheat. 
Deh6rain (11), Harz (22), Teller (38), and Willard and Swanson 
(45), have analyzed the materials found in the wheat kernel. 
Thatcher (40), Eckerson (15), and others (25, 39, 2), have followed 
the formation of these materials in the developing seed. Choate (5) 
has studied microchemicallv the changes in the carbohydrate and 
nitrogen content of seedlings during seven days germination in petri 
dishes. LeClerc and Breazeale (28), grew seedlings in various types 
of culture solutions for 15 days, and analyzed the seedlings for the 
mineral elements, ether extract, reducing and hydrolyzable sugars, 
pentosans, and fiber. Wimmer (44) studied the various parts of 
wheat plants, grown in soil, for minerals and starches at various 
periods, beginning at the time the plants were about 40 cm. high. 
METHOD 
Spring wheat of the Marquis variety, Clark and Martin (6), was 
grown in the greenhouse in earthenware containers, 17 by 19 cm., 
containing soil commonly designated “good field soil.” The maxi¬ 
mum water-holding capacity of the sou was approximately 50 per 
cent. The moisture content of the soil was determined and sufficient ^ 
water added at the time of planting the Seeds to bring the content ^ 
to “optimum.” The total weight was then recorded, and water 
was added frequently to maintain the optimum water content.; 
The plants for the freezing-point determinations were grown in 
November and December, and those for the chemical determinations 
in January and February. The temperature of the greenhouse was 
about 55° F. at night and 70° F. during the day. The plants were 
collected in the morning before they were exposed to the sun’s rays. 
Since the composition of the plants varies throughout the day and 
with the conditions varying on different days, as illustrated by the 
1 Received for publication July 26, 1924; issued December, 1926. 
2 The work represented by this paper was carried on under the direction of A. L. Bakke of the Iowa State 
College of Agriculture and Mechanic Arts. He suggested the experiment and submitted criticisms at differ¬ 
ent times, and the writer desires to make acknowledgment of his interest and help. Thanks are also 
expressed to R. M. Hixon, of the Chemistry Department. 
3 Reference is made by number (italic) to “Literature cited,” p. 741. 
Journal of Agricultural Research, 
Washington, D. C. 
( 727 ) 
Vol. XXXI No. 8 
Oct. 15,1925 
Key No. Iowa-10 
