376 



J. J. SKINNER 



A similar experiment growing wheat seedlings in distilled 

 water was made, using vanillin in amounts of 100 parts per 

 million. In both this and the former experiment the plants 

 were grown for twelve days. The effect of the manganese on 

 the action of vanillin is shown in the green weight figures in 

 table 3. 



TABLE 2 

 Effect of manganese sulphate on the aztion of salicylic aldehyde in distilled water 



TREATMENT 



Distilled water 



5 p. p.m. salicylic aldehyde 



5 p. p.m. salicylic aldehyde + 1 ji.p.m. Mn. 



5 p. p.m. salicylic aldehyde + 5 p. p.m. Mn. 



5 p.p.m. salicylic aldehyde + 10 p. p.m. Mn 



10 p.p.m. salicylic aldehyde 



10 p.p.m. salicylic aldehyde + 1 p.p.m. Mn. 

 10 p.p.m. salicylic aldehyde + 5 p.p.m. Mn. 

 10 p.p.m. salicylic aldehyde + 10 p.p.m. Mn. 



1 p.p.m. Mn 



5 p.p.m. Mn 



10 p.p.m. Mn 



GREEN WEIGHT 



grams 



1.37 

 1.18 

 1.32 

 1.32 

 1.50 

 0.87 



04 

 57 

 45 

 42 

 59 

 57 



TABLE 3 

 Effect of manganese sulphate on the harmful action of vanillin in distilled water 



TRE.\T.MENT 



Distilled water 



100 p.p.m. vanillin 



100 p.p.m. vanillin -|- 1 p.p.m. Mn 

 100 p.p.m. vanillin + 5 p.p.m. Mn 



1 p.p.m. Mn 



5 p.p.m. Mn 



The harmful effect of vanillin was here also partly overcome 

 by manganese used in small amounts. The oxidizing power 

 of the plant roots was determined in the different culture solu- 

 tions by the method described in Bulletin 56, Bureau of Soils,* 



^ Schreiner, O., and Reed, H. S., The role of oxidation in soil fertility. 

 Dept. Agr., Bur. Soils Bui. 56. 1909. 



U. S. 



