Viability of Seeds — A kamine 
39 
tained by the use of * 'running averages” of 
the original data. 
Paper bark seed 
The germination behavior of this seed in 
storage at various temperatures and relative 
humidities is graphically presented in Figure 
1. At each storage temperature, the relative 
humidity has influenced the viability of the 
stored seed (Fig. 1) . In general, the lower the 
humidity, the longer the seed is kept in a 
germinative condition. At room temperature, 
the 45 per cent relative humidity gave results 
slightly superior to the 30 per cent relative 
humidity. At 59° F., these two humidities 
were equally effective in prolonging the life 
of the seed. The 45 and 60 per cent relative 
humidities were slightly more effective than 
the 30 per cent relative humidity for main- 
taining the viability of the seed in storage at 
45° F. At each storage temperature, the seed 
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45" F. 
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- AIRTIGHT 
-OPEN 
59" F. 
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MAYS mays mays MAYS MAYS 
1944 1945 1946 1947 1948 
GERMINATION DATE 
Fig. 1. The effect of temperature and relative humid- 
ity on the viability of stored paper bark seed. 
kept in an airtight container maintained its 
viability just as well as that kept at 75 per 
cent relative humidity. The longevity curve 
for the seed stored open at room temperature 
lies approximately midway between the 60 
and 75 per cent relative humidity curves. 
Since the relative humidity of the air is ap- 
proximately 68 per cent, it seems logical to 
assume that the curve for the open storage 
should be in this position. Although no at- 
tempt was made to maintain the humidity in 
the cold chamber and no humidity measure- 
ments were made, it may be surmised that 
seed stored open at 59° F. was subjected to 
relative humidities in the neighborhood of 30 
and 45 per cent because the curves for these 
storage media lie in about the same plane 
(Fig. 1). At 45° F., the curve for the open 
storage lies in the neighborhood of the lower 
humidity storage curves after the first year of 
storage. 
When the graphs in Figure 1 are superim- 
posed and a critical examination is made of 
them, it becomes evident that the effective- 
ness of the two lowest relative humidities 
(30 and 45 per cent) in preserving the viabil- 
ity of the seed was not influenced by the dif- 
ferent storage temperatures. At relative 
humidities of 60 and 75 per cent and under 
airtight conditions, 45° F. and room tempera- 
ture were each equally more effective than 
59° F. in preserving the life of the seed. At a 
relative humidity of 90 per cent, 45° F. was 
more effective than 59° F., which in turn was 
more effective than room temperature in 
maintaining the longevity of the seed. In 
open storage, 59° F. maintained the viability 
of the seed more effectively than 45° F. and 
room temperature, which were equal to each 
other in effectiveness. 
It can be seen from Figure 1 that the via- 
bility of the seed of paper bark could be 
maintained for about 4 years even in open 
storage at room temperature. The optimum 
storage condition at room temperature, how- 
ever, was one in which the relative humidity 
was kept below that of the air. Generally 
