200 Smith and Butler. — Relation of 
The mean growth of a plant in solutions A and 'D was therefore better than 
that obtained in the full nutritive solutions used in Experiment i. It will 
be remembered that in Experiment i the plants grown in solution C were 
the heavier ; in Experiment 2 the plants grown in solution D are also the 
heavier. In Experiment 2 the mean dry weight of a plant grown in solu- 
tion D was 9*9 per cent, greater than that of a plant grown in solution A ; 
in Experiment i the difference in favour of solution C was 10-9 per cent. 
The behaviour of the plants grown in solutions C and D is therefore 
identical. We interpret this to mean that the change in concentration, 
not the salts used in its accomplishment, affected the rate of growth. 
A consideration of Table X also shows that root growth was relatively 
better in all solutions in Experiment 2 than in Experiment 1, the 
growth differences exhibited by the full nutritive solutions in the latter 
Table XI. Amount of and distribution of potassium in Blue stem Wheat 
plants grown 21 days in nutritive solutions A y B, and E. 
Total 
’ 
potas- 
sium 
Potassium 
Potassium 
Ratio of 
absorbed 
Nutritive solution 
No. of 
Amount of potassium 
utilized per 
potas- 
utilized from the 
used. 
plants . 
in 
gramme of dry 
sium 
per 
nutritive 
matter 
content 
gramme 
solution 
formed. 
of tops 
of dry 
by one 
Tops. 
Roots. 
Entire 
plants. 
Tops. 
Roots. 
to 
roots. 
matter 
formed. 
plant. 
Mg. 
Mg. 
■ Mg. 
Mg. 
Mg. 
Mg. 
Mg. 
Mg. 
Nutritive solution A 
30 
352 -io 
122.80 
474.90 
7 i,6 7 
79.02 
0.90 
73-49 
I 5 , 7 I 
Nutritive solution D 
30 
395 - 3 ° 
109.30 
505.20 
74.01 
74.82 
0.99 
74 * 1 8 
16.73 
Nutritive solution E 
30 
5 - 7 ° 
1.50 
7.20 
7-23 
7.98 
0.90 
7-36 
0-13 
being again faithfully reproduced. The better relative root growth in the 
case* of Experiment 2 is clearly not due, therefore, to the composition of 
solutions D and E, since it also occurred in solution A. 
The potassium content of the plants and its relative distribution in 
tops and roots is indicated in Table XI. A study of the table shows that in 
all cases the total potassium absorbed per gramme of dry matter formed was 
heavier in Experiment 2 than in Experiment J,but the distribution in roots 
and tops shows remarkably close agreement. In Experiment 1 the distri- 
bution ratio for the plants growing in solutions A and B is virtually 
identical ; in Experiment 2 the distribution, ratio for the plants growing in 
solutions A and E is identical. In Experiment 1 the potassium utilized per 
gramme of dry matter formed in the case of the plants growing in solution C 
is higher than that taken up by the plants growing in solutions A and B ; 
similarly, in Experiment 2 the plants growing in solution D have a higher 
requirement than those growing in solutions A and E. The plants grow- 
ing in solutions C and D have reacted similarly— further evidence that 
