140 University of California Publications in Agricultural Sciences [Vol.3 



tion of potassium and phosphoric acid as much as 70 per cent below 

 that of the control cultures. 



The work of Gile 18 is of interest in this connection. From ash 

 analyses obtained in investigating the cause of chlorosis in pineapples, 

 he found a direct relationship between the absorption of lime and 

 that of iron; that is, when the absorption of lime was high but little 

 iron was taken up. In soil studies Gile and Ageton 19 found no direct 

 relation between the lime content of plants and varying amounts of 

 lime and magnesia in the soil. 



A few investigations have been made on the absorption of specific 

 elements from solution, but these need only be mentioned in the 

 present connection. Maquenne 20 found that mercuric chloride causes 

 marked increase in permeability of the protoplasm, although it is not 

 necessarily absorbed itself in any considerable quantities. Marsh 21 

 correlates the amount of barium chloride present in the soil with 

 that found in the plant. Colin and De Rufz 22 always found absorbed 

 barium localized in the roots. 



A large number of analyses of plants grown under various condi- 

 tions have been reported, but the environmental factors have varied 

 so greatly as to render the results obtained of little value in the 

 present study. 



From this review it is evident that no quantitative study of the 

 elements actually absorbed from the nutrient solutions, balanced and 

 unbalanced, has been made with the idea in mind of a correlation 

 between the absorption of the various ions with their antagonistic 

 or toxic effects in solution cultures. 



Methods 



Barley was used as the plant indicator. The seeds were obtained 

 from the University Farm at Davis and were of a pure strain of the 

 Beldi variety. The method of sprouting the seeds, while simple, has 

 not been noted elsewhere and has given such excellent results, both to 

 the writer and to others, that it seems worthy of mention here in 

 detail. A piece of oilcloth about 12 x 18 inches was covered with sev- 

 eral thicknesses of paper toweling and the whole thoroughly wetted. 



i« Porto Rico Exp. Sta. Bull., 11 (1911). 



is Ibid., Bull. 16 (1914). 



20C.-R. Acad. Sci. (Paris), vol. 123 (1896), p. 898. 



-1 Bot. Gaz., vol. 54 (1912), p. 250. 



22C.-R. Acad. Sci. (Paris), vol. 150 (1910), p. 1074. 



