37° 



BOTANICAL GAZETTE 



[may 



of the presence of peroxidase was obtained, but not of oxidase; 

 however, when young growing wheat roots are treated with a solution 

 of alcoholic guaiac they instantly give a blue color, which deepens 

 when hydrogen peroxid is added. This indicates that the cells of 

 the plant root contain an oxidase, as Czapek has shown. 29 



TABLE II 



Relative oxidizing power of cultures and unplanted solutions of three nutrient 

 salts. Oxidizing power of plants grown in distilled water used as basis of comparison 

 (p.p.m. = parts per million). 



No. 



i 



2 



3 

 4 



5 

 6 



7 



Solutions 



Solution, 50 p.p.m. of N0 3 as NaNO 



Controls in distilled water (planted) 



3 (planted) 

 (unplanted) 



(planted) 

 (unplanted) 



P0 4 as Na 2 HP0 4 (planted) 



5o 



35 

 35 



5o 



a 



a 

 a 



K as KC1 



<< 11 



5° 



11 



a 



a 



(unplanted) 



Relative 

 oxidat ion 



100 

 282 



39 



7 2 

 6 



88 



3 



21 



A word may be introduced at this place concerning the possible 

 function of bacteria in producing oxidizing ferments which might 

 accomplish some of the effects noted. It is, of course, possible that 

 such organisms existed in the culture employed, since after filtering 

 the extracts no especial precautions were taken to keep them sterile, 

 and microorganisms which were on the roots of the plants would 

 certainly be introduced into the solutions. That these microorgan- 

 isms were responsible for any appreciable amount of oxidation in 

 the experiments described in this paper is hardly possible. In the 

 first place, the solutions used were not well adapted for a very thrifty 

 development of microorganisms, as was shown by their freedom 

 from turbidity, odors, or other indications. The definite zone * ^ 

 color produced when indicators like a-naphthylamine and benzidine 

 were used, and their close correspondence to definite zones of tissue 

 in the root show that the oxidation is performed only by agen 

 intimately connected with the roots. The colors due to oxidation 

 were most intense on the regions of the root where growth was nK* 

 active, whereas we would expect that the bacteria, if zonally 

 tributed, would be more abundant on the dying cells of the root cap 



3 » Annals of Botany 19:75 



1905 



