The effect of guanidin on plants * 
OSWALD SCHREINER AND J. J. SKINNER 
INTRODUCTION 
Guanidin has been found in some plants. It may arise from 
the oxidation of arginin. Arginin is a decomposition product of 
proteins and exists in plants, and it has also been found in soils. 
Interesting in this connection is the appearance of guanidin in seed- 
lings, as reported by Schulze,t which probably results by further 
changes from arginin. Guanidin can also be formed by the 
oxidation of guanin in the laboratory. 
Guanidin was shown to be toxic to plants, first by Kawakita § 
and later in this laboratory.|| According to Shibata, J who studied 
the effect of Aspergillus niger on a number of nitrogenous com- 
pounds, this mold had no effect on guanidin. Hutchinson and 
Miller** include guanidin among the nitrogenous compounds 
assimilated by plants. 
In the earlier experiments in this laboratory the guanidin 
carbonate was studied in various concentrations of distilled 
water. The wheat plants were killed in 9 days in solutions stronger 
than 100 parts per million. In all the lower concentrations, 
including 1 part per million, the wheat plants were seriously 
injured 
This harmful effect of guanidin has since then been more 
* Contribution from the Laboratory of Soil Fertility Investigations, Bureau of Soils. 
T Schreiner, O., and veprnien E. C. The presence of arginin and histidin in 
ett 
§ Kawakita, I. On the behavior arg dint to plants. Bull. Col. Agr. 
Tokio 6: 181. 1904 —05. 
|| Schreiner, O., Reed, H. S., and Skinner, J. J. Certain organic constituents of 
soils in relation a soil fertility. U.S. Dept. Agr. Bur. Soils Bull. 47. 1907. 
{ Shibata, K, Ther das Verlisinted von Amide spaltenden Enzymen bei 
teeny s Beitrage 5: 384. 1904 
** Hutchinson, H. B., and Miller, N. H. J. ER eet Someatiation: STERN 
and organic ‘SA = nitrogen by higher plants. Centralbl. Bakt. 30: 513. I9gIl. 
