AMERICAN 
JOURNAL OF BOTANY 
Vol. VIII February, 1921 No. 2 
INFLUENCE OF TEMPERATURE ON THE RELATIONS BE- 
TWEEN NUTRIENT SALT PROPORTIONS AND THE 
EARLY GROWTH OF WHEAT 
W. F. Gericke 
(Received for publication August 5, 1920) 
RusselP has stated that "Potash-starved plants are the first to suffer 
in a bad season or to succumb to disease. The Broadbalk wheat plots 
receiving potassium salts give conspicuously better results than others 
whenever the year is unfavorable to plant growth. . . . The badness of 
the season may be connected with high rainfall and correspondingly low 
temperatures." This statement emphasizes the fact that climatic condi- 
tions may exert no inconsiderable influence upon what may be regarded as 
the best set of proportions of the nutrient salts in the medium in which 
plants are rooted. What is a good set of salt proportions with one set of 
climatic conditions may not be a good one with another climatic complex, 
etc. Results obtained from an experimental study carried out in 191 8-19, 
in the Laboratory of Plant Physiology of the Johns Hopkins University,^ 
seem to bear on this general and important proposition, and some of these 
results are here reported in a preliminary way. 
The investigation was planned to bring out the relations between main- 
tained temperature, on the one hand, and the physiological properties of 
various nutrient solutions, on the other. The germination and early seedling 
phases in the development of "Marquis" wheat were studied, the grains 
being supported on paraffined mosquito netting held just beneath the 
surface of the solution, which was renewed every 24 hours. The containers 
were glass tumblers having a capacity of 300 cc. Twenty-five seeds were 
used for each test, and all tests have been repeated at least once. Seven 
^ Russell, E. J. Soil conditions and plant growth. 2d ed. 1915 (pp. 42, 43). 3d ed. 
1917 (pp. 43, 44). 
2 This study was carried on as part of a cooperation between the committee on salt 
requirements of representative agricultural plants, of the Division of Biology and Agri- 
culture of the National Research Council, and the laboratory named above. It was 
partially financed from the war-emergency funds of the Council. The writer wishes to 
express his appreciation of much kindly interest and advice received from Prof. B. E. 
Livingston. 
[The Journal for January (8: 1-58) was issued March 9, 192 1.] 
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