40 
PACIFIC SCIENCE, Vol. V, January, 1951 
speaking, at temperatures of 59° and 45° F., 
open storage was about as effective as the low 
relative humidities in preserving the life of 
the seed. 
Brush box seed 
The germination behavior of the seed of 
brush box in storage under various conditions 
is depicted graphically in Figure 2. In general, 
regardless of the storage temperature, seeds 
stored at the low relative humidities main- 
tained their viability better than those stored 
at the high humidities (Fig. 2). At each tem- 
perature, the 45 per cent relative humidity was 
optimum, being superior even to the 30 per 
cent. The difference between these two hu- 
midities in their effectiveness in increasing 
the longevity of the seed, however, became 
smaller as the storage temperature was low- 
ered. At room temperature, the germination 
curve of the seed stored in airtight containers 
h- 
UJ 
6 ERMINATI ON DATE 
Fig. 2. The eflfect of temperature and relative humid- 
ity on the viability of stored brush box seed. 
approached that of the seed in the 60 per cent 
relative humidity storage toward the latter 
part of the storage period. With prolonged 
storage at 59° the airtight storage curve 
was near the 30 per cent relative humidity 
storage curve. At 45° F., the airtight storage 
was surpassed only by the 45 per cent relative 
humidity storage in effectiveness in maintain- 
ing the viability of the seed. As in the case of 
the paper bark seed (Fig. 1), the germination 
curve of the seed stored open at room tem- 
perature lies approximately midway between 
the curves of the 60 per cent and 75 per cent 
relative humidity storage (Fig. 2). At 59° F., 
the open storage curve again lies between the 
60 and 75 per cent realtive humidity curves, 
but at the end of the storage period, it had 
approached the curve of the higher one of 
these humidities. At 45° F., the open storage 
curve actually lies below that of the 75 per 
cent relative humidity curve. 
When the graphs in Figure 2 are superim- 
posed, it is seen that when the seeds were 
stored at 30 per cent relative humidity, 45° F. 
was more effective than 59° F. and room tem- 
perature in maintaining the viability of the 
seeds. The two latter temperatures were about 
equally effective in this respect. The effective- 
ness of the 45 per cent relative humidity in 
prolonging the germinative power of the seed 
was not influenced by the different tempera- 
tures employed. At relative humidities of 60 
and 90 per cent and in airtight storage, it was 
found that the lower the storage temperature, 
the longer the seeds remained viable. Tem- 
peratures of 45° and 59° F. were equally more 
effective than room temperature; in open 
storage seeds kept at 59° F. remained in a 
viable state longer than those kept at 45° F. 
Seeds stored open at the latter temperature in 
turn kept better than those stored at room 
temperature. 
Since the longevity of the seed at 45 per 
cent relative humidity was the same at any 
storage temperature and since this humidity 
was the optimum for seed storage, it followed 
that even at room temperature, the seed of 
