INFLUENCE OF PHOSPHATE ON THE TOXIC ACTION 



OF CUMARIN 1 



J. J. Skinner 



In connection with a study of the different effects produced 

 as the result of the action of several organic compounds on seedling 

 wheat, presented in a former paper, 2 it was noted that the presence 

 of phosphate in the nutrient solutions employed was able to mini- 

 mize or entirely overcome the toxic effect of the cumarin on the 

 seedlings. The effects of the cumarin on plant development are 

 strikingly shown on the seedling wheat. The leaves are shorter 

 and broader than is normal for wheat, and only the first leaves 

 are usually unfolded, the other leaves remaining wholly or par- 

 tially within the swollen sheath; such leaves as do break forth 

 are usually distorted and curled or twisted. The disappearance 

 of this characteristic behavior of the cumarin affected plants was, 

 therefore, an additional criterion of the beneficial effect of the 

 phosphate in the nutrient cultures, as well as the improved growth 

 and better root development of the plants in general. The nutrient 

 solutions contained nitrate as sodium nitrate, potassium as potas- 

 sium sulphate, and the phosphate was added in the form of mono- 

 calcium phosphate. 



Attention was called in the earlier paper to the fact that the 

 observation there recorded was obtained with the calcium acid 

 phosphate, and that the observed result may be caused, therefore, 

 by the salt as a whole rather than by the phosphate radical con- 

 tained therein, or by other specific qualities of the salt or other 

 constituent parts, namely by its acid properties or the fact that 

 calcium is present in the compound. 



Several experiments were planned so as to eliminate the possi- 

 bility of calcium producing the result noted, and to present the 



1 Published by permission of the Secretary of Agriculture. 



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



modified by fertilizer salts. Bot. Gaz. 54 : 3 1-48. 191 2. 

 2 4Sl 



[Botanical Gazette, vol. 54 



