Potassium to Growth in Plants. 
2 T I 
The effect of delayed additions of potassium is seen to have . very 
serious results even when the plants are only grown three days without this 
element present, and when grown nine and twelve days, respectively, with- 
out it not the slightest recovery follows its addition. It will also be noted 
that corresponding with the decrease in total dry matter formed there is 
a decrease in root growth. Potassium added to plants grown in its absence 
for nine and twelve days is entirely without effect, the ratio of top weight to 
root weight remaining similar to that of the plants grown throughout in 
a solution free from potassium —further proof that the plants had been 
unable to make any recovery. 
But if the plants were unable to show any recovery from potassium 
starvation if the element were not furnished within six days, a consideration 
of Table XXII shows that they were, nevertheless, capable of absorbing 
potassium when it was offered. The relative distribution of potassium in tops 
and roots per gramme of dry matter formed is the same whether the plants 
have been grown in its absence or whether it has been offered to them at 
once or only after the lapse of a certain time. It will be noticed, however, 
that the amount of potassium utilized per gramme of dry matter formed is 
distinctly affected by the length of time the plants are permitted to obtain 
it. It will also be apparent from the table that the presence of potassium 
does not directly influence the amount of dry matter formed. In fact, 
a simple calculation will show the following relation to exist between 
potassium utilized and dry matter formed : 
In the full nutritive solution there was formed by i grm. potassium 
15-33 grm. dry matter. 
(Mean of solutions A and F) 
When potassium was added after 3 days there was formed 
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When potassium was absent ,, „ 
by 1 grm. potassium 
1 5-65 grm. dry matter, 
by 1 grm. potassium 
1 7*76 grm. dry matter, 
by 1 grm. potassium 
23-34 grm. dry matter, 
by 1 grm. potassium 1 
30-64 grm. dry matter, 
by 1 grm. potassium 
131-06 grm. dry matter. 
The above figures do not sustain the view that potassium is necessary 
to the synthesis and translocation of carbohydrates, and we have in fact 
noticed that Blue stem Wheat plants growing in the absence of potassium 
form and translocate starch as readily as plants growing in the presence of 
this element. Plants were grown in solution F plus potassium and in 
solution F less potassium in numbers sufficient to allow specimens being 
withdrawn from time to time over a period of three weeks. One jar of 
plants of each of the nutritive solutions was always taken for one examina- 
tion, part of the plants being used in the test for starch, the remainder in 
the test for translocation. Eight days after the experiment was begun 
crinkled areas — that is, the first symptoms of potassium starvation — began to 
