Apr. is, i9ai 
Susceptibility of Injured Seeds to Molds 
in 
Table V .—Germination of hand-thrashed wheat after immersion for various periods in 
saturated copper-sulphate solution 
Duration of immersion in copper sulphate. 
iH hours. 
6 hours. 
8 hours. 
10 hours. 
16 hours. 
Control. 
untreated. 
Percentage of germina¬ 
tion. .. 
100 
100 
92 
82 
25 
IOO 
As Walldeh (23) and Volkart (22) report, only those cracks directly 
over the embryo permit injury from a 5-minute dip in a i-pound to 
4-gallon solution (PI. 22, A). Our experiments also show that a similar 
dip in a saturated solution does not affect germination if the injury is 
over the endosperm. However, if longer exposures are made, the 
chemical eventually penetrates to the embryo with fatal results. After 
a soak of 1 hour in a 1-pound to 4-gallon solution, seeds with a scratch 
through the seed coat to the endosperm are slightly injured (usually the 
roots show some deformity or stunting), and after 6 hours the percent¬ 
age of germination is low and growth of the seedling retarded. In a 
saturated solution, injury is extreme after 1 hour. Of course all seeds 
with the injury over the embryo are killed by these exposures in either 
strength. Seeds apparently unbroken are uninjured after 6 hours in a 
saturated solution, although there are occasional exceptions to this. 
The data from the experiments are presented in Table VI. 
Table VI .—Germination of wheat with broken and unbroken seed coats, as affected by 
cop persulphate treatment 
Condition of seed and strength of solution. 
Germination after exposure of — 
5 minutes. 
i hour. 
6 hours. 
Seed coats unbroken: 
Per cent. 
Per cent. 
Per cent. 
1 to 4 solution.. 
IOO 
IOO 
IOO 
Saturated solution. 
IOO 
IOO 
a IOO 
Seed coats broken over endosperm: 
1 to 4 solution. 
IOO 
92 
68 
Saturated solution. 
28 
0 
Seed coats broken over embryo: 
1 to 4 solution... 
53 
0 
0 
Saturated solution. | 
0 
0 
0 
o The resistance of unbroken seeds to a 6-hour exposure in a saturated copper-sulphate solution varies 
with temperature and other conditions at present unknown. 
The seedlings of all samples giving low germinations were very much 
deformed and stunted, the roots being especially injured (PI. 23). 
A lime dip usually increases the percentage of germination of injured 
seeds (PI. 22, B). However, in badly broken seed, lime can not prevent 
copper-sulphate injury because the solution enters rapidly and injures 
