Potassium to Growth in Plants. 
199 
the third day the effect of absence of potassium was perceptible. The 
daily increment of growth of the plants in solution E during the first seven 
days was very nearly uniform, though distinctly less rapid than that of the 
plants in solutions A and D. After the seventh day, however, there is 
a marked falling off in the daily increment of growth, and on the eighteenth 
day stagnation is imminent ; whereas in the plants in the full nutritive 
solutions growth continues uninterruptedly and sustainedly. It will also be 
noticed that the rate of growth of the plants in solution A is a little less 
Table X. Green and dry weights of Blue stem Wheat grown 21 days in 
nutritive solutions A , D, and E. 
Ratio of 
Nutritive solution 
No . of 
Total weig 
■Jit of plants . 
Weight 
Weight 
tops to 
used . 
plants . 
Green . 
Dry . 
of tops . 
of roots . 
roots . 
Grm. 
Grm. 
Grm. 
Grm. 
Grm. 
Nutritive Solution A 
5 
9-4600 
0.8099 
0.5219 
0.1880 
3 - 3 i 
5 
14.1160 
1.1238 
0.8727 
0-2511 
3-47 
5 
17.3300 
1.2883 
. 0.9459 
0.3424 
2.76 
5 
12.4260 
1-0415 
0.7998 
c - 2 4 i 7 
3 - 3 i 
5 
12.2380 
0-9924 
o -7573 
0.2351 
3.22 
5 
14.1390 
1.2062 
0.9119 
0.2943 
3-09 
Mean 
1 
2.6570 
0.2154 
0.1636 
0.0518 
3-i6 
N utritive solution D 
5 
1 2.2640 
1.0783 
0.8472 
0.2311 
3.66 
5 
11.7530 
1 -0402 
0.8319 
0-2083 
3-99 
5 
14.4320 
1.2864 
1 .01 18 
0.2746 
3.68 
5 
1 1- 7410 
0.9618 
0-7575 
0.2043 
3 - 7 i 
5 
1 3 * 53 20 
I-G 34 
0.9245 
0.2489 
3 - 7 2 
5 
14.6910 
1.2695 
0.9732 
0-2963 
3.28 
Mean 
1 
2-6138 
0.2270 
0.1782 
C.04S8 
3-65 
Nutritive solution E 
5 
1-2768 
0.1606 
0.1326 
0-0280 
4-73 
5 
1. 1 294 
0.1563 
0.1276 
0-0287 
4-45 
5 
1.4652 
0.1764 
0.1428 
0-0336 
4- 2 5 
5 
0-8076 
0-1582 
0.1289 
0.0293 
4.40 
5 
1-2048 
0.1568 
0-1250 
0.0318 
3-93 
5 
1.1698 
0.1692 
0-1328 
0-0364 
3-63 
Mean 
1 
0.2351 
0.0326 
0-0263 
0-0063 
4.17 
than that of the plants in solution D, though apparently this difference 
would not have persisted had the experiment continued longer. 
The green and dry weights of the entire plants, the tops and roots, and 
the ratio of top growth to root growth at the conclusion of the experiment are 
given in Table X. The data given in the table show that the total dry 
weight of a plant grown in the absence of potassium was 0*0326 grm., that is, 
0-9 mg. more than was obtained in Experiment 1 — a wholly negligible 
quantity. In the case of the plants growing in solutions A and D, the 
mean dry weights of a plant were respectively 0*2154 grm. and 0*2270 grm. 
