214 Smith and Butler. — Relation of 
starvation are not overcome, and are more marked than the figures on rate 
of growth given in Table XXIII, taken in themselves, would lead one to 
expect. The data presented in Table XXIV would also lead one to expect 
that the total amount of potassium utilized per gramme of dry matter 
formed would be approximately the same for plants growing in the presence 
of potassium from the beginning or suffering from a period of starvation 
up to and including twelve days. The data presented in Table XXV 
confirms this expectation, and shows that while the amount of potassium 
utilized per gramme of dry matter formed is slightly irregular, there is no 
indication of a relation such as was found in the water-culture, experiment 
(see Table XXII) between the potassium requirement and delayed additions 
of the element. In the present instance, however, the period of growth 
was of sufficient duration for the plants longest starved to show well- 
marked evidences of recovery, which was not the case in Experiment i. 
Table XXIV. Effect of delayed additions of potassium on the dry 
weight produced by Blue stem Wheat plants. 
No.. of 
No. of 
Method of treatment. 
' No. of plants 
Total dry weight 
Mean dry 1 weight 
pot. 
plants. 
zvith 
of plants. 
of one plant. 
heads. 
Grm. 
Grm. 
1 
Potassium present from the 
6 
5 
3.2044 
o- 534 i 
beginning. 
2 
Potassium added after 3 days 
7 
7 
3.9672 
0-5668 
3 
->•> >> >} 6 
7 
6 
4-4738 
0.6391 
4 
5 5 V 55 9 55 
8 
7 
4 ‘ 83 3 3 
0-6040* 
6 
5 5 5 5 55 12 5 5 
7 
7 
4 -Q 373 
0.5768 
6 
5 5 5 , 55 l 7 55 
10 
9 
3.6262 
0.3626 
7 
„ 55 55 2 2 „ 
10 
7 
2 - 5 OI 4 
0.2531 
8 
„ absent 
10 
1 
0.4766 
VO 
!>. 
■*+■ 
O 
6 
In Experiment i the wheat was grown twenty-one days in the nutritive 
solutions, in the experiment under consideration eighty-three days elapsed 
between the setting up and taking down ; in other words, Experiment 2 
was run almost four times longer than Experiment i. If we assume that 
the daily increment of potassium absorption of the plants growing in the 
absence of potassium was the same in both experiments, then in Experi- 
ment 2 the plants should contain four times the amount of this element 
present in the plants of Experiment i. The amounts actually were 0-34 mg. 
per plant for Experiment 2, and 0-09 mg. per plant for Experiment 1. 
Obviously, therefore, the differences in potassium requirement shown by 
plants subjected to delayed additions in Experiments 1 and 2 in a measure 
represent recovery effected. We say in a measure represent the recovery 
effected, because the disturbing effect on the plant metabolism that exists 
during the interval of starvation and in the interval of time before the 
establishment of equilibrium following the addition of potassium retards 
