,909) SCHREINER &• REED-OXIDIZING POWER OF ROOTS 357 



The study of the. oxidizing enzymes which are given off by the 

 roots of plants, i. e., extra-cellular oxidation, has received less atten- 

 tion, and it is to this particular field that the present study belongs. 



Molisch' 3 appears to have been the first to demonstrate the 

 oxidizing power of root secretions and to show their enzymotic 

 nature. He found that the root secretion was capable of oxidizing 

 various organic substances, such as guaiacol, pyrogallol, and gallic 

 acid. His work showed that there was considerable active secretion 

 on the surface of growing roots, and that this secretion had definite 

 powers to effect changes in organic substances. 



Czapekm in making a general study of root secretions, followed 

 some of the investigations made previously by Molisch. From 

 experiments upon the action of seedling roots upon starch paste and 

 sugar solutions, he regarded it probable that the growing roots 

 produce only diastase or inverting ferments, although exact proof 

 could not be offered. He believed, however, that the experiments 

 of Molisch failed to prove the production of oxidizing enzymes by 



roots. 



The ideas of the oxidizing powers of roots set forth by Molisch 

 are well corroborated by the investigations of Raciborski 15 upon 



the oxidizing powers of plant tissues. 



In his work reagents were used which were so nearly non-toxic 

 that they could be added to solutions in which plants were grwn. 

 In some experiments the reagents were added to water culture, 

 containing the growing plants; in others, strips of filter paper * men 

 had been saturated with the reagent were applied to the surface 

 P°wing roots. The substances used for showing the oxidizing power 

 « growing roots were a-na P hthylamine, benzidine, phenolphthalin, 

 ^rrous ammonium sulfate, Barbadoes aloes, guaiac, phlonazin, 



Pyrogallol, leucomethylene blue, etc. 



The extra-cellular oxidation by the roots of the ph™™ 

 »*sl was found to be strongly localized and limited to the absorbing 

 *face of the root. The most intensive oxidation occurs m he 

 "Son covered by the root hairs. After the death of the root ha.rs, 



13 Sitzb. Akad. Wiss. Wien. Math. Nat. Kl. 96:84- i» 88 - 



14 Jahrb. Wiss. Bot. 29:321. 1896. 



15 Bull. Acad. Sci. Cracovie i90$-3& 668 > 6 93- 



