204 



M. M. McCooL 



solutions stronger than N/30 NaCl, whereas shght development of tops 

 occurs in cultures containing N/10 KCl. The lethal concentration of 

 sodium for roots is just below N/75. 



TABLE 3. Experiment with Pea and Wheat Seedlings, Continued for Ten Days. 



Data for Ten Plants 



Composition of solution 



Distilled water as the solvent 



N/5XaCl 



N/10 NaCl 



N/20 NaCl 



N/30 NaCl 



N/50 NaCl 



N/75 NaCl 



Distilled water 



Full nutrient solution as the solvent 



N/3 NaCI 



N/4 NaCl 



N/5 NaCl 



N/10 NaCl 



Nutrient solution 



Soil cultures 



N/1 NaCl 



N/2 NaCl 



N/3 NaCl 



N/5 NaCl 



N/10 NaCl 



Distilled water 



Pea 



Wheat 



Increase 



in length 



of tops 



(centi- 

 meters) 















0.25 



0.50 



3.00 



6.00 



Increase 

 in length 

 of roots 

 (centi- 

 meters) 























3.00 



7.00 



Increase 

 in length 

 of tops 

 (centi- 

 meters) 



7.00 



Increase 

 in length 

 of roots 

 (centi- 1 

 meters) 























3.50 



8.00 











1.00 



6.00 



7.50 











2.00 



7.00 



8.50 





 



SHght 

 6.50 

 6.00 





 



Slight 

 7.00 

 6.50 







1.00 

 9.00 

 9.00 







2.00 



8.00 



10.00 



Harter (1905) gives .054 N as the average limit of pure solutions of 

 sodium chlorid for several varieties of wheat. In his experiments the 

 roots of the seedlings were in contact with the solutions only twenty- 

 four hours. This undoubtedly accounts for the higher values that he 

 obtained. 



