looS] SCHRETNER dr* REED— TOXIC PLANT CONSTITUEXTS 89 



The ketones, as is well known, are distinctly toxic to plants, and taken 

 together these two properties undoubtedly account for the action of 



chinone upon plants. 



Cinnamic acid occurs in small amounts in the secretions of certain 

 plants and its esters are found in the leaves of various tropical plants. 

 By proper treatment it yields all the different phenol acids. 



True (:oo) found that a concentration of cinnamic acid equivalent 

 to m/i 2,800 (i 2 ppm.) prevented the growth of the root tips of Lupinus 

 albus in 24 hours. He also found that sodium cinnamate was toxic 

 to root tips when employed in a concentration of w/Soo (184 ppm.j. 



Using a slightly different method, the results obtained with wheat 

 seedlmgs varied, naturally, from those obtained with lupine. The 

 same relations, however, hold true in both cases. Cinnamic acid is 

 strondv toxic for seedlings, and its sodium salt is moderately toxic. 



A concentration of loo ppm. of cinnamic acid was fatal to wheat 

 plants and 25 ppm. was injurious. Cinnamic acid is particularly 

 toxic to root growth, and it was only in the concentrations below 25 

 ppm. that anything like normal root growth was exhibited. When a 

 wheat root is'kiUed by cinnamic acid it is not swollen nor discolored 

 in the usual fashion, but on the contrary appears perfectly white. 



Sodium cinnamate is much less toxic than cinnamic acid. Wheat 

 plants were not killed by a concentration of 1000 ppm. and were not 

 injured at concentrations weaker than 100 ppm. 



Cumarin is found in a number of different plants and gives the 

 odor which is characteristic of Hierochloa and MelHotus. It is a 

 lactone of cumaric acid which may be regarded as orthoxjxinnamic 

 acid. It is also of interest to note that Gosio (:o6) has found that 

 cumarin may be formed from carbohydrates by the action of certain 

 mold fungi,' e.g., Aspergillus glaucus, A. novus, A. flavescens, and 



A. varians. 



Orthocumaric acid and o-hydrocumaric acid (melilotic acid) are 



found in Alelilotus (sweet clover) in addition to cumarm. Para_ 

 hvdrocumaric acid, although it has not been reported in plants, is of 

 interest on account of its relation to tjTosin. Through the action ot 



.._ .•_ t..^„-;^ ;= -hrntpTi nn and ammonia liber- 



bacteria the amid gr* 



umaric 



Klebs °'q6) found that' Conjena minor was quickly kiBed 



