176 



M. M. McCooL 



oxid per acre by dissolving in a considerable volume of water and sprinkling 

 on the soil." 



Experiments conducted by Stoklasa (1911) show that manganese and 

 aluminium, when present in small quantities in nutrient solution, each 

 stunulates several species of plants. Stoklasa is of the opinion that these 

 elements are of importance in photosynthesis, inasmuch as they collect 

 mainly in the leaves. Further, the presence of these elements in the 

 culture solution results in the formation of larger leaves. 



The nutrient solution employed was made up as follows: 



K2SO4 1 .00 gram 



MgCla 0. 50 gram 



NaNOa . 50 gram 



FeS04 0.01 gram 



CaS04 . 05 gram 



Distilled water 1 liter 



The addition of 2/1000 or 3/1000 atomic weight of either aluminium 

 or manganese to one liter of nutrient solution causes toxic action. The 

 addition of 1/1000 atomic weight of either element results in stimulation; 

 the stimulation is greater when 1/2000 atomic weight of both aluminium 

 and manganese are added to the nutrient solution than when the same 

 concentration of either element is added alone. Stoklasa's results are as 

 follows : 



Composition of solution 



Dry weight of ten plants (in grams) 





Wheat 



Rye 



Oats 



Barley 



Buck- 

 wheat 



Nutrient solution 



53.8 

 56.1 

 55.9 



50.0 

 62.8 

 59.8 



82.2 



78.8 

 80.9 

 82.1 



65.2 

 86.0 



85.8 



93.6 



66.2 

 68.0 

 68.6 



60.9 

 70.0 

 71.3 



78.5 



62.3 

 67.1 

 68.8 



61.3 

 75.2 



72.8 



89.4 



15.8 



Nutrient solution+1/1,000 at. ■nrt.*Al 



Nutrient solution+1/1.000 at. wt. Mn 



Nutrient solution+1/1,000 at. wt. A1+ \ 



1/1,000 at. 'Ri;. Mn / . . 

 Nutrient solution+ 1/2,000 at. wt. Mn .... 



Nutrient solution+ 1/2,000 at. wt. Al 



Nutrient solution +1/2,000 at. wt. Mn+ \ 



1/2,000 at. wt. Al / . 



20.2 

 20.3 



11.8 

 21.4 

 21.1 



26.3 



* Atomic weight. 



