'm 



WHEAT RESISTANCE TO TOXIC SALTS, 



Renting the limit for the hipine, and equal to that for the most resist- 

 ant varieties of wheat. 



Coupin <* found the toxic limit of wheat in sodium carbonate to be 

 about 1.1 per cent. In view of the fact, however, that he noted the 

 death of the whole plant and not the root tips, the limit of concen- 

 tration as determined by him would necessarily be much higher. 



RESULTS WITH SODIUM BICARBONATE. 



The limits in })ure solutions of sodium bicarbonate are shown in 

 the following table : 



Of all the salts used sodium bicarlionate seems to bring out the least 

 variation in resistance so far as these experiments are concerned. The 

 least resistant variety was Maraouani and the most resistant Kharkof, 

 which were able to survive in a 0.0225 and 0.03 normal solution, 

 respectively. These results do not dili'er to an important extent from 

 those of Kearney and Cameron for Lupinus alhtis, the toxic limit of 

 which was slightly low^er (0.02) than that for Maraouani wheat. 



The writer finds sodium carbonate to be about two and six-tenths 

 times as injurious to wheat when in equivalent concentration as 

 sodium bicarbonate. Kearney found the difference to be even greater 

 in the case of maize, the ratio being about -t to 1. Coupin '' reverses 

 the relative toxic order of these two salts. This difference in the 



o Sur la Toxieite du Chlorure de Sodium et de TEau de Mer a I'Esard des 

 Vegetaux. Itevue Generale de Botanuiue, 10: 180 (1898). 



6 Sur la Toxieitt' des Composes de Potassium et de rAnunonium a FEtxard des 

 Vegetaux Superieurs. Kevue Geuerale de Botaui.ciue, 12:180 (1900). 



