June, 1922] 
MUENSCHER ABSORPTION OF SALTS 
how much ash might have been found in the plants if the salts in the solu- 
tion entered with the water in which they were in solution. These data 
show that in every case the quantity of salts in a volume of solution equal 
to the volume of water absorbed and transpired was at least as great as the 
quantity of ash found. In every case but one, namely, in the humid cul- 
tures of the summer series, the plants took up more water than was neces- 
sary to supply the salts found, provided they all entered with the solution. 
Table 8. Comparison of the Average Quantity of Water Transpired with the Average Ash 
Content per Culture under Various Conditions 
Cone, of 
Solution 
Cc. of Water 
Transpired 
Total Weight of 
Ash Determined 
Ash Equivalent of 
Solution 
Summer Series 
Dry 
.14% 
350. 
.147 
.2800 
Humid. 
.14% 
170. 
•135 
.1360 
Light 
.14% 
833. 
.322 
.6640 
Shade 
.14% 
400. 
.121 
.3200 
Winter Series 
Light 
.07% 
659.6 
.182 
.2638 
Shade 
.07% 
382.7 
.087 
•I531 
Light 
.28% 
431.6 
.163 
.6906 
An examination of the data presented in the above tables shows that 
the relation between transpiration and the absorption of salts as deter- 
mined under the conditions of these experiments varies with the method by 
which transpiration is changed. If there is a definite relation between the 
quantity of water transpired and the quantity of salts absorbed, one would 
expect that doubling the transpiration in plants would considerably increase 
the absolute weight and percentage of ash in plants. This is not the case. 
An examination of the data of dry weights, ash weights, and ash con- 
tent expressed as percentages of dry weights presented in tables 1,2, and 
5 shows that in general an increase in dry weight is accompanied by a rela- 
tively greater increase in the ash weight. These data are brought together 
for comparison in table 9. In the dry-humid cultures the slightly lower 
dry weight of the tops, roots, and total plants of the cultures grown in the 
humid chamber is in every case accompanied by a slight decrease not only 
in absolute quantity but also in the percentage of ash. This same 
relation between increase in dry weight and ash is found between the light- 
shade cultures of the winter series. In the light-shade cultures of the 
summer series a pronounced increase in the dry weight of the tops is also 
accompanied by an increase in total ash weight, but the percentage of ash 
is decreased from 20.34 to 18.91 percent. The percentage of ash in the 
roots is increased from 20.35 to 30-55 percent when the total dry weight 
and ash are increased. This increase in the percentage of ash in the roots 
was more than enough to balance the decrease in the tops, so that the per- 
