jane, 1920.1 : \ . #o ME SOL UTIOX CULTURES OF WEEAT 89 



as promising: — 



In conclusion, it may be stated that a 3-salt solution without 

 potassium may produce very satisfactory growth of very young wheat 

 plants if the other essential elements are all present and if the partial 

 concentration of the di-hydrogen-phosphate salt is very low, as com- 

 pared with the partial concentration of the nitrate and sulphate salts 

 combined. It would be valuable to know what would be the effect of 

 substituting other phosphate salts, such as the mono-hydrogen- 

 phosphates, etc., in place of the di-hydrogen forms employed in the 

 preliminary experiment here described. 



Laboratory of Plant Physiology, 



The Johns Hopkins University, 



Baltimore, March, 1920. 



Legend for figure 1. 



Diagrams showing good and poor solutions of each of the six 

 types. Good solutions are denoted by circles, poor ones by triangles. 

 Each angle of the triangle represents a solution having five-sevenths of 

 its concentration due to one salt and one-seventh to each of the other 

 salts. The salt named at any angle is the. one that predominates in 

 the solution represented by that angle. Note the similarity of all six 

 diagrams and that good growth usually corresponds to low partial 

 concentration of (H 2 P0 4 ) 2 , while high partial concentrations of this 

 atomic group generally correspond to poor growth. 



