1922] GERICKE—ROOT SYSTEMS 207 
measure of growth obtained by the cultures of class B. That the 
cultures of class A failed to give the measure of growth obtained by 
the cultures of class B must undoubtedly be attributed to some 
effects of the previous treatment, and of which the large roots in 
this case apparently may be considered but an incident. In this 
connection it can be argued that the cultures of class A were stunted 
and did not possess the same potential power or capacity for growth 
as did those of class B, and therefore regardless of any possible bene- 
ficial effect, if these large roots meant a greater surface for absorp- 
tion, this could not compensate to overcome the stunted effects suf- 
fered by the plants. Undoubtedly the capacity of a plant to grow 
is affected by the rate of absorption of nutrients, and vice versa, 
the rate of absorption of nutrients is affected by the growth of the 
plants, so that the absorbing capacity of any comparable unit area 
of root surface must vary with conditions. It appears, therefore, 
that the data of the cultures grown in solution no. 1, taken by 
themselves, do not give any indication as to what effects the differ- 
ent root systems had in the results. 
The results obtained from solution no. 2 are decidedly different. 
The seedlings having large roots, when placed in this ‘‘very poor 
nutrient solution, produced about two and one-half times as much 
dry matter as did the other class of seedlings grown in this solution. 
The yield of the cultures of class A grown in solution no. 2 were 
approximately of the same magnitude as those grown in solution 
no. 1. The yield of the cultures of class B having comparatively 
small roots when placed in solution no. 1 was about five and one-half 
times larger than that of the corresponding cultures grown in solu- 
tion no. 2. The explanation for the differences in growth obtained 
from the two classes of seedlings grown in solution no. 2 seems to be 
due to differences in the extent of the root systems these cultures had 
when placed in the media. It is quite obvious that the great differ- 
ence in total dry weight obtained from the two classes of cultures 
grown in solution no. 2 is due to the very small growth made by 
the cultures with small roots, and not to any exceptionally good 
growth made by the cultures with large roots. The effect of solu- 
tion no. 2 upon the one class of seedlings (class B) was to prevent 
its making such a measure of root growth as could be necessary to 
enable the plants to make even a moderate measure of top growth. 
