VANILLIN AND SALICYLIC ALDEHYDE 



375 



The absorption of salts was also less from the solutions con- 

 taining vanillin than from their controls without vanillin. The 

 absorption of each nutrient element for each culture is given 

 in the table. Considering all the cultures, the phosphate ab- 

 sorption was reduced 21%, the nitrate 10%, and the potash 

 33%. The absorption of nitrate was less interfered with by the 

 vanillin than either phosphate or potassiima. 



The results with cowpeas are in harmony with those with 

 wheat seedlings where it was shown that the harmfulness of 

 vanillin was very slight in solutions high in nitrate content, and 

 that its effect was less in cultures composed principally of nitrate 

 than in cultures composed principally of phsophate or potassium.' 

 The roots of plants have an oxidizing power which is increased 

 by nitrate fertilizers."* Vanillin is changed or even destroyed 

 by oxidation. 5 Thus this compound when used in nutrient 

 solutions composed of a high per cent of nitrates is probably 

 changed and does not remain as such to have its effect on plant 

 growth. 



EFFECT OF MANGANESE ON THE ACTION OF VANILLIN AND 



SALICYLIC ALDEHYDE 



The effect of manganese on the harmfulness of salicylic alde- 

 hyde was studied in an experiment growing wheat plants in dis- 

 tilled water. The wheat seedlings were grown in culture jars 

 holding 250 cc. of pure distilled water. The plants grew for 

 twelve days. The results are given in table 2. 



As seen from the green weight figures in the table, the salicylic 

 aldehyde was harmful in distilled water in amounts of 5 and 10 

 parts per million. Manganese sulphate in amounts of 1, 5 and 

 10 parts per million of manganese overcame its effect partly 

 with the lower concentration and entirely with the larger amount. 

 Its influence is shown nicely in the cultures shown in figure 2. 



' Schreiner, O., and Skinner, J. J., The toxic action of organic compounds as 

 modified by fertilizer salts. Bot. Gaz. 54: 31. 1912. 



* Schreiner, O., and Reed, H. S., The role of oxidation in soil fertility. U. S. 

 Dept. Agr., Bur. Soils Bui. 56. 1909. 



" Schreiner, O., and Reed, H. S., Jour. Amer. Chem. Soc. 30: 85. (1908). 



THE PLAXT WORLD, VOL. 19, NO. 12 



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