554 



EXPERIMENT STATION RECORD. 



Usually the experiments lasted about 10 days, and from 60 to 100 seedlings were 

 used to establish the toxic limit in each case. The results are brought together in 

 the following table: 



Resistanci of wheat varietiesto various salts in terms of fractional parts of a normal culture. 



The ash constituents of the wheat seedlings were also determined, but no correla- 

 tion between the amount or the composition of the ash and the resistance of the seed- 

 lings to saline solutions was established. The author compares some of his results 

 with those obtained by other investigators in work with lupine and maize, as follows: 



Differences in the toxicity of the same salts to wheat, lupine, and maize. 



It may be observed from this table that while magnesium sulphate is the most 

 toxic to the wheat and the lupine of all the salts used, it is the least injurious to maize. 



It is shown that the ratio of resistance of one variety of wheat to another varies 

 for different salts, being in general greater for the more toxic salts and smaller for 

 those less toxic in their effects. The greatest ratio of resistance between varieties, 

 1:3, was observed in the tests with sodium carbonate and magnesium chlorid. In 

 the magnesium sulphate tests this ratio between the most and the least resistant 

 varieties was 1:2. The average resistance of a variety was not correlated with its 

 resistance to the different individual salts. 



It is pointed out that a variety averaging least in resistance may be much more 

 resistant to a particular salt than the variety averaging highest, and that this fact 

 may be of value in selecting varieties for soils containing an excess of some one salt. 

 Varieties from localities where toxic salts are abundant in the soil are most resistant 

 in water cultures to these salts, while those from humid regions are less resistant. 

 Individual variation makes the establishment of the toxic limit in some varieties 

 more difficult than in others. In all cases the resistance of a variety must be worked 

 out for itself. 



All the salts used, except sodium carbonate and sodium chlorid, acted as stimulants, 

 the elongation in some cases being twice that occurring in hydrant water. It was 



