VALUE OF CERTAIN NUTRITIVE ELEMENTS 
plants grown in the normal solutions. However, the dry weight of 
the grain produced by the former plants is two thirds of the dry weight 
of the grain produced by those grown in the normal solutions. The 
decrease in dry weight of grain resulting from the growing of plants in 
potassium-deficient solutions is therefore not in proportion to the 
decrease in the production of total dry matter; for although fewer 
kernels are formed when plants are grown in potassium-deficient solu- 
tions, those that are formed are heavier than an equal number of 
kernels from plants grown in the normal solutions. Grain formation 
takes place at the expense of vegetative growth. 
The high grain-straw ratio in plants grown in potassium-deficient 
solutions may be partially explained by tracing the movement of 
potassium during the development of the plant. Analyses show that 
^ potassium is localized first in the growing regions of the young seedling ; 
later, during the development of the flower, it appears in large quanti- 
ties in the region of grain formation; and finally it is stored in the 
mature kernel rather than in the straw. As the potassium salts are 
very soluble, they are readily transferred from the embryonic tissues 
of leaves and stems to the embryonic region of the flower. Since an 
abundance of potassium seems to be necessary for meristematic de- 
velopment, the activity of the embryonic regions of the vegetative 
parts will be checked by the decrease in their potassium supply during 
flower formation, the result being a high grain-straw ratio. 
Table 6 
The Average Yield of Grain and Straw in Plants Grown in the Normal Solution and in 
Solutions with One Nutrient Element in Each Case Reduced to One Tenth Normal. 
No. Det. 
per Year 
Solution, 
Deficient Ele- 
ment Given 
Weight of Grain in 
Gm. 
Weight of Straw in Gm. 
1915 Crop 
1916 Crop 
19 1 7 Crop 
1915 Crop 
1916 Crop 
191 7 Crop 
4 
Normal 
5.329 ± 2 
6.986 ± I 
6.362 =b 0 
7.08 ± 2 
14.77 ±2 
28.08 d= 0 
2 
Mg 0.1 
5.804 ± I 
29.62 ± 2 
2 
Ca 0.1 
5.212 ± I 
6.645 ± 0 
3.999 ± 0 
7.96 d= 2 
17.21 ±3 
20.75 ± 2 
2 
K 0.1 
2.968 ± I 
5.660 it 2 
3.268 ± 0 
3.51 ±2 
10.22 ± 41 12.68 ± 0 
2 
P 0.1 
1. 142 d= I 
.390 ± I 
.665 =b 0 
1.59 ± I 
.84 ± I 
2. II ± 2 
2 
N 0.1 
1.767 ± I 
.120 =t I 
.679 =b 0 
2.23 ± I 
.29 =b 0 
2.02 =b 0 
The general decrease in production of dry matter by plants grown 
in potassium-deficient solutions may be due to the fact that potassium 
acts in some way as a condenser or catalyzer in the process of trans- 
location and subsequent condensation of the carbohydrates and 
