3o6 
H. D. WAGGONER 
seven days and the results obtained recorded as indicated in Table IV. 
The daily percent of germination of the five hundred untreated seeds 
is shown in the last column. In the other columns is recorded the 
germination of seeds of an initial water content of 4 percent, 9 percent, 
14 percent, and 18 percent respectively, when heated at 80° C. for 
thirty minutes. 
Table IV 
The Retardation in Germination Caused by Varying Water Content at Temperature of 
80° for JO minutes 
Water Content of Seeds when Heated 
44 
9^' 
Mi 
Check 
Un- 
treated 
Percent of germination the ist dav 
6% 
.6 
0 
0 
30 
" 2d " 
21% 
54 
0 
0 
45 
" " " " 3d " 
35% 
17 
74 
0 
14 
" 4th " 
17% 
24.2 
II 
0 
3 
" " " " 5th " 
3% 
10 
6 
0 
2 
" 6th " 
3.6 
2.2 
0 
" " " " 7th " 
0 
4 
0 
0 
Total percent of germination 
83% 
60.8 
27.0 
0 
95 
The maximum daily percent of germination in the check (45 per- 
cent) occurred on the second day, while in the treated seeds the highest 
number of seeds germinated on the third or fourth day. Seventy-five 
percent of the untreated seeds germinated in the first two days as 
compared with twenty-seven percent for those of 4 percent moisture, 
six percent for those of 9 percent moisture and zero percent for those 
of 14 percent moisture. The resulting injury due to the increased 
water content is shown by the rapid decrease in total germination of 
the samples, namely: 95 percent, 83 percent, 60.8 percent, 27 percent 
and o percent respectively. The retardation in the germination of 
radish seeds becomes greater as the injury due to the treatment 
becomes more marked. 
To correlate the results found in the literature with my own, it 
became necessary to repeat, under control conditions, the different 
methods heretofore used. In the preceding section (Tables I, II, III) 
the intimate relation between initial water content and viability at 
high temperatures was definitely determined, and the suggestion 
made that the wide difference in the lethal temperature of seeds of 
similar kinds as reported by different investigators was to be sought 
in the initial water content of the seeds or in the method employed 
that would allow an increase or decrease of this water content during 
the heating process. 
