TEMPERATURE EFFECTS IN PLANT METABOLISM 1 
By W. E. Tottingham 
Associate Professor of Agricultural Chemistry, University of Wisconsin 
INTRODUCTION 
In recent years considerable attention has been given by ecologists 
to climatic factors as determining plant distribution. Among the more 
recent publications in this field is the work of Livingston and Shreve (27) . 3 
The extensive observations of Bonnier (j, 2) upon anatomical and 
physiological modifications in plants of the same species, grown at dif¬ 
ferent altitudes, are also noteworthy in this connection. This inves¬ 
tigator has recently detected a complete change of variety in plants 
subjected for several years to such change of environment. To the 
physiologist, adaptations of this sort are explainable by the assumption 
that changes in the intensity of the various climatic factors disturb the 
chemical and physical equilibria which direct the growth process. 
Followers of agricultural science are familiar with general relations 
between variations of climate and differences in the chemical composi¬ 
tion of plants. Thus Hall (9, p. 83) states: 
Even on the Rathamsted plots, where the differences in the supply of nutrients are 
extreme and have been accumulating for 50 years, the composition of the grain changes 
more from one season to another than it does in passing from plot to plot. 
Beginning with the work of Richardson (31, p. 67; 32 , p. 23) on analyses 
of grains from various regions of the United States considerable work 
has been done in this country upon the problem of environmental effects 
in the chemical composition of plants. Le Clerc ( 18 , 19) has shown that 
the hot arid climate of Kansas is conducive to high protein content of wheat 
grain, irrespective of the types of soil tested by him. Richardson found 
no difference in composition of maize from different regions. No decided 
correlation between climatic factors and the composition of sweetcorn 
was found by Straughn and Church ( 38) in an investigation confined 
to the Atlantic Coast States. On the other hand, Wiley (41) found a 
distinct correlation between the sugar content of the sugar beet and the 
latitude of the State experiment stations which cooperated in his inves¬ 
tigation. He concluded that temperature was the effective climatic 
factor in this case. 
Apparently there exists an open question as to whether such climatic 
influences as have been mentioned here operate only upon the plant or 
act also indirectly through modification of the composition of the soil. 
Thus, while Lawes and Gilbert (17) found the proportion of grain in the 
wheat crop of Great Britain decreased by excessive rainfall, they at¬ 
tributed the effect partly to loss of nitrates from the soil by leaching. 
Furthermore, Gericke (7, 8) has shown that the protein content of wheat 
1 Accepted for publication Jan. 22, 1923 Published with the permission of the Director of the Wisconsin 
Agricultural Experiment Station, Madison. Wis. 
3 Reference is made by number (italic) to “Literature cited,” p. 28-30. 
Journal of Agricultural Research 
Washington, D. C. 
afk 
Vol. XXV, No. 1 
July 7, 1923 
Key No. Wis.-2i 
