REDUCTION BY ROOTS? 
OSWALD SCHREINER AND M. X. SULLIVAN 
The roots of many plants, such as wheat, have an oxidizing 
power (1). This property is readily shown by certain chromogens, 
alphanaphthylamine, benzidine, phenolphthalin, aloin, guaiac, 
pyrogallol, etc. When chromogens like alphanaphthylamine and 
benzidine are used, the colors due to oxidation are shown on the 
root itself. The most marked oxidation is shown by a narrow 
but very distinct band of color just back of the root cap. Then 
comes a practically colorless zone and then a broad colored zone, 
the color becoming less intense toward the upper part of the root. 
In regard to the practically colorless zone or the zone with little 
color just back of the region of intense coloration, it seemed as if 
the lack of color might be due to a reducing power, a reductase 
or possibly an antienzyme. 
The possibility of an antienzyme is suggested by the work of 
BERTEL (2), who showed that with the exclusion of oxygen there 
accumulated in the cells of the lupine roots larger quantities of 
tyrosine than are usually found. The tyrosine which arises from 
the protein degradation in the early stages of the seedling’s growth 
is normally oxidized by the enzyme tyrosinase to homogentisic 
acid and oxidation products of the latter. With the exclusion of 
oxygen, this oxidation is retarded and tyrosine accumulates. 
Subsequently CzapEK (3) showed that ‘‘a short time after the 
beginning of geotropic induction there appears a retardation of 
the normal destruction of tyrosine to be recognized by an accumu- 
lation of homogentisic acid.” The cause of this retardation he 
attributed to the development of specific antioxidase which inhibits 
the normal activity of the oxidase of the root tip. 
Reducing properties have been found in animal organs, in 
microorganisms, and in plant juices. The reducing power of the 
animal organism was shown first by EHRLIcH (4), who used alizarin 
* Contribution from the Laboratory of Soil Fertility Investigations. Published 
Y permission of the Secretary of Agriculture. 
121} [Botanical Gazette, vol. 51 
