[Vor. 7 
16 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
(Series 2, Corn) 
SALT REQUIREMENTS AND H-ION CONCENTRATION IN RELATION TO GROWTH 
Total | Gr. wt. | Total | Greatest " 
No. Culture gr. wt. | of roots | dry wt length Initial Pa 
indices | (gms.) | (gms) | (gms.) | (cm) ew 
1 AcO 25.44 7.63 2.325 32.33 3.4 
2 Ac /10 33.52 7.96 2.567 | 32.91 5.8 
3 Ac /20 26.14 6.36 2.170 | 30.71 6.3 
4 Ac /40 13.28 5.10 1.642 22.26 iá 
5 AcNa 29.94 7.89 2.001 32.49 3.45 
6 AcM 29.48 8.10 2.139 27.57 5.4 
7 Ac 1/ 31.56 8.18 2.337 | 32.56 3.35 
8 Ac 3/ 28.60 6.06 1.888 32.06 3.15 
9 BcO 26 .46 8.60 2.515 | 33.71 6.6 
10 Be 1/ 26.19 9.34 2.232 33.31 6.4 
11 Be 2/ 27.86 10.29 2.151 33.03 5.6 
12 e 5/ 35 7.75 2.108 30.50 3.2 
13 BcK;/10 32.25 11.48 2.476 33.51 7.0 
14 BeK /10 29.48 9.96 2.453 29.46 
15 BcCa 30.42 11.80 ~ 2.852 34.55 7.3 
16 Be /5 31.20 10.68 2.530 34.65 7.4 
17 Be /10 31.55 9.90 2.767 33.98 8.6 
* Heavy precipitate. 
tions, the second series was placed upon the rotating table and 
rotated throughout the period of culture. The rotating table 
employed was that previously described (Duggar and Bonns, 
'18) except that there was substituted for the special pot plat- 
forms a continuous platform constructed above the radiating 
arms and the secondary motion was, of course, eliminated. 
The wheat was grown 21 days, while the corn and peas were 
grown 24 days. One change of solution was made after about 
12 days of growth. It is, therefore, a rather severe test of 
growth quantities when infrequent renewals of solutions are 
made. The water loss from transpiration was supplied about 
every second day. 
In determining the hydrogen ion concentration of the solu- 
tions employed at the beginning of the experiment it was found 
that the active acidity of solution A was 3.4, consequently much 
greater than the theoretical. This was found to be due to the 
