560 
AMERICAN JOURNAL OF BOTANY 
[Vol. io, 
percolation through the sand medium provides unusually favorable con¬ 
ditions for the complete development of the plants. 
In the constant-drip cultures and in the aerated-drip cultures it was 
found that the roots had penetrated to the bottoms of the culture vessels, 
notwithstanding the nearly saturated condition of the substratum in this 
region, while in the simple cultures and in the aerated cultures root develop¬ 
ment in the lower portions of the substratum was much less pronounced. 
Table 2 gives the ratios between dry weights of the different plant parts 
and the total dry weights of the plants which are given in the last column 
of the table, the values, of course, representing averages in each case. As 
indicated in the table, the total average dry weights of the plants grown 
Table 2. Ratios of Average Dry Weights of Plant Parts to Average 
Total Dry Weights of Plants Grown in Sand Cultures 
Cultures 
Tops 
Roots 
Total Dry 
Stems 
Leaves 
Fruit 
Total 
Weights 
Simple solution. 
O.I42 
.149 
.140 
•157 
O.238 
•234 
.223 
.254 
0.562 
•553 
•574 
.524 
O.942 
•936 
•937 
•935 
0.058 
.064 
.063 
.065 
38.861 
37.687 
47-913 
60.581 
Simple aerated solution. 
Drip solution. 
Aerated-drip solution. 
under the several experimental conditions show large differences. On the 
other hand, the development of the plant parts relative to the total yields 
produced under the different experimental treatments is strikingly similar, 
as is indicated by the pronounced uniformity of corresponding ratio values. 
Solution Cultures 
Table 3, which is similar to table 1, gives the numerical data of the 
plants grown in solution cultures corresponding to the sand cultures pre¬ 
viously described. From a comparison of the data for simple solution 
cultures with those of the aerated solution cultures, it will be observed that 
with these, as with the corresponding sand cultures, aeration produced no 
Table 3. Relative Dry Weights of Plants Grown in Solution Cultures 
Cultures 
Tops 
Roots 
Total Dry 
Weights 
Stems 
Leaves 
Fruit 
Total 
Simple solution. 
1.00* 
1.00 
I.OO 
I.OO 
I.OO 
1.00 
(6.386) 
(8.876) 
(4.640) 
(19.896) 
( 2 . 324 ) 
(22.220) 
Simple aerated solution. 
.983 
I.064 
776 
I.II 7 
.812 
Drip solution. 
.815 
•952 
3-775 
U 567 
•743 
1.503 
Aerated-drip solution. 
1.412 
I.296 
5.392 
2-339 
1-433 
2.199 
* The dry-weight values of the simple solution cultures are taken as 1.00 and corre¬ 
sponding values of the other cultures are expressed in terms of these. The actual dry weights 
of the simple solution cultures are given in parenthesis, in grams. 
