548 SCHREINER & SKINNER: EFFECT OF GUANIDIN ON PLANTS 
* Again the characteristic effect of the guanidin was observed 
in the cultures containing nitrate, and the depressed growth is 
shown by the green weight in the table. With creatinin the 
effect of guanidin was not apparent either in appearance or in 
the green weight obtained. 
SUMMARY 
Guanidin, as carbonate, is shown to be harmful to wheat, 
corn, cowpeas, and potato plants. It produces an effect similar 
to a physiological disease. The plant is normal for a few days, 
then begins to show a spotted appearance on leaf and stem. This 
effect develops until the plant is bleached to a considerable extent, 
with final collapse. 
This harmful effect of guanidin on plants is augmented by 
the presence of nitrate and increases with the amount of nitrate 
present. 
Sources of nitrogen, other than nitrate, did not show this 
same effect. The organic nitrogenous compound asparagin, as 
well as the beneficial soil constituent creatinin, appeared in fact 
to be able to counteract the effect of guanidin itself. 
U. S, DEPARTMENT OF AGRICULTURE, 
BUREAU OF SOILS, 
WASHINGTON, D. C. 
