1909] SCHREINER &• REED— OXIDIZING POWER OF ROOTS 385 



cumarin, and santonin. The compounds were dissolved in distilled 

 water and the resulting solutions used as cultures, taking care that 

 the concentrations chosen were not so great as to be fatal to wheat 

 plants within the duration of the experiment. Vanillin was used 

 at the rate of 100 parts per million, cumarin 10 parts per million, 

 and santonin in a saturated solution, which was nearly 100 parts per 

 million. The growth of the plants, as measured by transpiration 

 and stated in figures, taking the growth of similar plants in distilled 

 water as 100 in each case, was: vanillin, 63; cumarin, 81; santonin, 

 75. After the plants had grown in their respective solutions for 

 12 to 14 days, ioo m * of aloin were added to each and the results 

 noted on the following day. The results agreed in showing no color 

 indications of oxidation in any of the cultures where the toxic com- 

 pounds were present, although the roots growing in the control cul- 

 tures in distilled water showed by the red color produced that a 

 material amount of oxidation had been accomplished. 



That the mere presence of organic materials did not inhibit the 

 oxidation was shown by an experiment employing a solution of 

 leucine which was slightly beneficial to the growth of wheat seedlings 



. . _ . ; ■« • i. -~;~^ ^ ir\ inn narts 



in solution cultures. 



54 and 98 per cent, respectively, were very favorable to oxidation and 

 Produced a much deeper aloin red than the cultures in distilled water. 

 It can onlv be concluded, therefore, that the toxic organic com- 

 pounds studied were deleterious to oxidation because of their toxic 

 Properties, and it appears that they were even more deleterious to 



oxidation than to plant growth 



"Aiuauon man to plant growin. 



The oxidizing action of the plants upon toxic organic substances 

 ^ a phenomenon which has been pointed out by the authors in a 

 Previous papers and will be referred to again later. The expenmen s 

 Presented in that paper also showed that the addition of sodium 

 ^trate and calcium carbonate to solutions of toxic organic compound* 

 *ent far toward decreasing their harmful effects, and in some cases 

 overcame them entirely. That the organic salts and the physiolog^ 

 cal activities of the plants working together had accomplished the 

 H^.._,. .'. . \ . u™,n hv both plant growth and 



38 



Jour. Amer. Chem. Soc. 30:85. 1908. 



