

1909] SCHREINER &> REED— OXIDIZING POWER OF ROOTS 



369 



TABLE I 



Relative oxidizing power of cultures and unplanted solutions of Takoma lawn 

 soil extract with and without the addition of fertilizer ingredients. Oxidizing power 

 of plants grown in distilled water used as the basis of comparison (p.p.m. = parts per 

 million). 



Xo. 



1 

 2 



3 

 4 



6 



7 

 8 





 10 



11 



12 



14 



Solutions 



Distilled water (planted) ) 

 Distilled water (planted) ) 

 Extract Takoma lawn soil (planted) 



Average 



a 

 tt 

 tt 



a 

 tt 

 tt 

 tt 

 tt 

 tt 

 tt 

 tt 



tt 

 tt 

 a 

 tt 

 tt 

 it 

 tt 

 a 

 tt 

 tt 

 tt 



it 

 it 

 tt 

 tt 

 it 

 tt 

 a 

 tt 

 it 

 tt 

 a 



ti 



a 



tt 



tt 

 a 

 a 

 a 

 tt 

 a 

 tt 

 a 



tt 



(unplanted) 



a 



+ 2000 p.p.m. CaC0 3 (planted) 



+ 2000 



+ 2000 " " (unplanted) 



+ 2000 



4- 50 p.p.m. NaN0 3 (planted) 



a 

 it 

 a 



tt 

 it 



ti 



+ 

 + 

 + 



5° 



5° 



ii 



<< 

 << 



(unplanted) 



u 



Relative 



oxidation 



IOO 



88 



74 

 8 



"3 

 63 



19 



25 



98 

 63 



24 



17 



affected the oxidizing powers. The plants grown in extracts of poor 

 SMl possessed less oxidizing power than the controls in distilled water, 

 but the oxidizing power was increased by the addition of calcium 

 carbonate. The addition of sodium nitrate did not show any marked 

 •ncrease to the oxidation in those solutions in the time of the expcri- 

 m ent, although its effect as shown in later experiments is always 

 eneficial to oxidation. 



The point to be emphasized in this experiment, which has not 



been previously brought out, is that the soil extract unplanted pos- 



esses a comparatively feeble power of oxidation, as shown by the use 



of Phenolphthalin, and that the addition of calcium carbonate and 



sodium nitrate slightly increased this small oxidizing power. 



An additional experiment was performed, using three different 

 salts in distilled water. The results of this experiment, which 



v en in Table TI, confirm those of the foregoing experiment in the 

 "tf extract. The cultures were made in duplicate and the figures 

 present the averages of each pair. 



The enzymotic nature of the oxidizing processes was next investi- 

 & at ed, using alcoholic guaiac. When alcoholic guaiac is added to 

 a solution in which wheat roots have been growing for a time, evidence 



are 



gK 



