1920] 
DUGGAR—H-ION CONCENTRATION AND NUTRIENT SOLUTIONS 29 
TABLE XIII 
(Series 4, III—Wheat [dry, high temperature]) 
SALT REQUIREMENTS AND H-ION CONCENTRATION IN RELATION TO GROWTH 
Total Total Greatest Pu 
No. pein gr. wt. dry wt. length 
um (gms. | (gms.) (cm.) | Initial | After gr. 
1 AwO 2.4. .395 19.70 3.4 4.8 
2 Aw /5 5.50 .582 26.23 4.6 5.8 
3 Aw /10 5.61 601 24.90 5.8 6.1 
4 Aw 1/ 1.78 287 17.14 3.35 3.4 
5 Aw 3/ 1.55 248 16.33 3.15 3.4 
6 AwNa 3.66 441 23.70 3.45 3.6 
ri AwM 3.35 390 21.89 5.4 5.0 
8 BwO 7.43 658 26.54 6.6 7.2 
9 Bw /5 7.25 733 30.97 7.4 7.6 
10 Bw /10 5.64 493 22.94 8.6 8.6 
11 Bw 1/ 4.72 554 24.38 6.4 8.6 
12 Bw 5/ 5.42 566 25.19 3.2 1.9 
13 Bw 10/ lí. 092 6.67 2.8 2.9 
14 BwK;/10 6.40 615 26.58 7.0 7.9 
15 BwCa 7.99 765 28 .62 7.9 8.2 
16 CwO 4.49 510 21.60 4.2 1.2 
17 Cw /5 4.97 576 23.43 6.4 7.6 
18 Cw /20 3.32 450 20.20 7.6 8.2 
19 Cw 1/ 4.80 491 23.66 3.6 7.0 
20 Cw 5/ 2.00 298 19.02 3.2 5.0 
21 CwNa 4.50 522 24.00 4.2 7.4 
BwCa. Several other cultures in the B block, notably Bw 1/ 
and Bw 3/, exceed slightly all those of the C block by either of 
the 2 important criteria, that is, green weight or dry weight. 
Under these conditions the tolerance of high hydrogen ion con- 
centration is generally marked, as shown in cultures AwO, 
AwNa, Bw 5/, and Cw 1/. Likewise the range of tolerance 
and of strong growth is considerable. 
In section 11 of this series with wheat (table xır) it is the infer- 
ence from the data that when grown for a longer period (25 
days) under cooler conditions wheat is less resistant to high 
hydrogen ion concentration. This is shown in part by the fact 
that the 4 cultures yielding highest in green weight are BwCa, 
AwM, BwO, and Aw /5. "There is, however, no striking falling 
off, on the whole, as hydrogen ion concentration increases to 
