Dec. 18,1916 
Assimilation of Iron by Rice 
5i7 
Table X .—Comparative weights of rice plants grown in two solutions where the iron was 
unavailable, but with the leaves treated with ferrous sulphate 
Nutrient 
solution. 
1 
Quantity of iron per 
liter. 
Source 
of iron. 
Treatment. 
£ 
Green weight of stalks 
and leaves. 
Oven-dry weight of 
stalks and leaves. 
Oven-dry weight of 
roots. 
Alkaline.. 
Gm, 
0. 008 
[Ferrous 
< sul- 
[ phate. 
|Leaves not brushed.. j 
1-6 
7-12 
Gm. 
2. 47 
2. 48 
Gm. 
0-89 
•39 
Gm. 
O. 131 
. 126 
Do. 
. 008 
. .do. 
/heaves brushed withf 
l ferrous sulphate. \ 
13-18 
19-24 
14. 63 
i 5 - 95 
2. 14 
2. 32 
.630 
. 602 
Neutral ... 
. 008 
jDialyzed 
\ iron. 
jheaves not brushed.. j 
25-30 
3 i_ 36 
.90 
•99 
. 16 
. 19 
. 062 
. 062 
Do. 
.. 008 
...do. 
fLeaves brushed withf 
\ ferrous sulphate. \ 
37-42 
43-48 
11.44 
9.40 
1. 69 
1. 40 
.463 
• 383 
Average 
oven-dry 
weight of— 
ilks and 
leaves. 
i 
& 
V 
£ 
th 
$ 
Gm. 
Gm. 
°* 39 
O. 52 
2. 23 
2. 85 
. 18 
. 24 
i- 50 
I. 92 
Experiment ii (Effect of increasing the phosphates in the neutral 
solution).—Since there is always more or less iron in the nutrient solu¬ 
tions precipitated as phosphates, it was important to see whether in¬ 
creasing the phosphates in the solution would affect the growth of plants. 
In this test the neutral solution used in the preceding experiments was 
compared with a solution which contained double the quantity of mono- 
and dibasic potassium phosphate, but which was otherwise similar. 
Two tests were run at different times, one using ferric chlorid as the 
source of iron and one using ferric citrate. For the sake of conciseness 
they are combined in one table. 
In the test with ferric chlorid two plants were grown in each flask, 6 
flasks were taken as a unit and the units triplicated for each treatment. 
In the test with ferric citrate one plant was grown in each flask, 12 flasks 
were taken as a unit, and the units duplicated for each treatment. The 
data on the growth of these plants are given in Table XI. 
The ferric-chlorid plants were all of rather poor color, those with 
p.002 gm. of iron per liter being poorer than those with 0.008 gm., but 
no differences were apparent between plants in the ordinary and double¬ 
phosphate solutions. The ferric-citrate plants in both ordinary and 
double-phosphate solutions were of good color at all times. 
In regard to growth and iron content, there were no appreciable dif¬ 
ferences between plants in the ordinary and double-phosphate solu¬ 
tions, although the very slight differences in growth were always in favor 
of the ordinary solution. 
