1920] 
DUGGAR—H-ION CONCENTRATION AND NUTRIENT SOLUTIONS 33 
XVII 
(Series 4, I—Peas [moist, high temperature]) 
SALT REQUIREMENTS AND H-ION CONCENTRATION IN RELATION TO GROWTH 
Total | Gr. wt.| Total | Greatest Pa 
No. CHE gr. wt. | of roots | dry wt length 
pev (gms.) | (gms.) | (gms.) (cm.) Initial | After gr. 
1 A 12.53 4.15 1.010 28.46 3.4 3.5 
2 Ap /5 13.82 4.15 1.059 31.05 4.6 4.2 
3 | Ap/10 13.92 | 3.87 | 1.062] 13.25 | 5.8 5.8 
4 Ap 1/ 1.55] 3.42 .937 28.00 2.00 4.7 
5 Ap 3/ 11.99.] 3.17 .990 29.68 3-10 5.8 
6 ApNa 12.50-|] 3.98 1.024 31.42 3.45 4.6 
7 ApM 12.81 | 3.93 .966 30.00 5.4 4.6 
8 BpO 10.60 3.02 .839 25.87 6.6 6.4 
9 Bp /5 13.17 | 3:04 .957 31.97 | 7.4 7:5 
10 Bp /10 9. 3.11 .746 32.47 8.6 7.6 
11 Bp1/ 1t Hf 3.47 .809 23.37 6.4 7.0 
12 Bp 5/ 11.12| 2.89 .842 26.22 3.2 5.8 
13 Bp 10/ 7.59 meek .623 23.29 2.8 4.8 
14 BpK; /10 12.30 | 3.61 .936 26.62 7.0 PERS 
15 BpCa 12.55]. 3.50 .937 29.57 7.9 7.6 
16 CpO 12.44 3.39 .074 25.34 4.2 5:2 
17 Cp /5 8.19 2.16 .657 21.66 6.4 6.2 
18 Cp /20 10.52 2.93 .928 22.37 7.6 1.5 
19 Cp 1/ 12.50 3.50 .982 26.02 3.6 5.0 
20 Cp 5/ 6.93 | 2.01 .605 21.36 3.2 4.2 
21 CpNa 10.72 3.06 .923 22.35 4.2 5.4 
servable in cultures Ac /10, Be /5, Be /10, BeCa, and Cc /5. 
Corn grown under conditions of high temperature and low 
humidity exhibits a maximum in AcM followed respectively by 
BcK;/10, Ac /5, BeCa, and Be 1/. An examination of block A 
would seem to indicate that Px 3.4 to 4.6 is entirely favorable in 
this medium, but there is a striking difference between Ac/10 
“and AcM, which is not readily explainable. 
In table xvii it may be noted again that slight variations in 
the culture medium do not materially affect the growth of peas 
when grown under the conditions there indicated. The A 
solution with the addition of alkali yields, it is true, the maxi- 
mum growth quantities, but these quantities are only slightly in 
excess of those obtained with the same solution unmodified or 
of several cultures in the B block, notably Bp /5, BpK;/10, and 
3 
