THE EFFECT OF VANILLIN AND SALICYLIC ALDE- 

 HYDE IN CULTURE SOLUTION AND THE ACTION 

 OF CHEMICALS IN ALTERING THEIR INFLUENCE* 



J. J. SKINNER 

 Bureau of Plant Industry, Washington, D. C. 



A study of the effect of organic compounds on plant growth 

 in distilled water, in nutrient culture solutions, and in soil in 

 pots and in the field has been made by this laboratory and the 

 results reported from time to time. An interesting develop- 

 ment in this line of work is the experiments bearing on the effect 

 of the inorganic salts, such as sodium nitrate, calcium phos- 

 phate, potassiimi sulphate, calcium carbonate and the manganese 

 salts in altering the action of certain of these organic compounds 

 on plants. 



With wheat plants in culture solutions vanillin and dihydroxy- 

 stearic acid have their harmful effects greatly diminished by 

 the addition of sodium nitrate or by calcium carbonate, whereas 

 their harmfulness remains unimpaired by phosphate or potash 

 fertilizers. Nitrate is an oxidizing substance and it has been 

 shown that root oxidation is increased greatly by its use, where- 

 as vanillin decreases root oxidation and is capable of being oxi- 

 dized. The effect of these chemicals is to promote biological 

 processes that change or destroy these organic compounds. 

 Quinone has its harmful action reduced by potash salts; it is 

 an active oxidizing substance, while potash reduces root oxida- 

 tion. Thus these two substances antagonize each other in 

 their effects. On the other hand, the harmful effects of cimiarin 

 and salicylic aldehyde are partially remedied by phosphates, 

 and calcium carbonate also alters the effects of saUcylic aldehyde. 



Field experiments also show that the harmfulness of vanillin 



* Contribution from Soil Fertility Investigations published by permission of 

 the Secretary of Agriculture. 



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