Dec. is, 1923 
Influences Affecting the Growth of Bean Seedlings 539 
be expected, since the initial amount of reserve material seems to deter¬ 
mine the total growth product, while the temperature acts as an accel¬ 
erating factor. In order to illustrate the relation between seed-weight, 
temperature, and growth-rate, we may consider the time required to ob¬ 
tain a growth of 140 mm. for the large and for the small seeds, respectively: 
At io° C., large and small seeds require 9.8 days; at 15 0 , large seeds, 7.8 
days; small seeds, 8.8 days; at 20°, large seeds 3.1 days; small seeds, 8.5 
days. It can be seen that in the case of large seeds a normal temperature 
coefficient exists, while in the case of small seeds the temperature coeffi¬ 
cient is abnormally small. This would seem to suggest that the amount 
of food stored in the seeds is of major importance for early growth. 
SUMMARY 
Bean seeds of different sizes (weights) were selected and grown in dark¬ 
ness in greenhouse soil with 60 per cent of its water-holding capacity, con¬ 
stant relative air humidity (60 per cent), and at constant temperatures 
of 5 0 , io°, 15 0 , and 20° C., until the seedlings stopped growing or col¬ 
lapsed. Robertson’s equation, considering growth as an autocatalytic 
chemical reaction, was applied. 
Under these uniform conditions plants of seeds of a heavier weight show 
a decided advantage over plantlets from seeds of light initial weight. 
Temperature acting as an accelerating factor increases the advantage 
of plants grown from seeds with a greater initial weight. 
