4 



BULLETIN" 108 ; U. S. DEPARTMENT OF AGRICULTURE. 



The figures in the table show a decreased growth due to the sali- 

 cylic aldehyde. Ten parts per million reduced growth from 100 to 

 60, or 40 per cent, 50 and 100 parts per million were also extremely 

 harmful, and very little growth occurred in the 200 parts per million 

 solution. 



EFFECT ON COWPEAS. 



An experiment with cowpeas, similar to that with corn seedlings, 

 was made, using the same concentrations of salicylic aldehyde and 

 the same nutrient solution. The plants grew in the solutions from 

 June 15 to June 28. One plant was used in each culture. 



The effect of the aldehyde on the cowpea plants was similar to 

 that with wheat and corn. In Plate II, figure 2, are shown the 

 plants as affected by the aldehyde. From this it is seen that amounts 

 larger than 10 parts per million are extremely harmful to the cow- 

 pea. 



In Table II is given the green weight of the cowpea plants taken 

 at the end of the experiment, and then relative growth. 



Table II.— Effect of salicylic aldehyde on cowpeas in nutrient solutions. 



No. 



Treatment. 



Nutrient solution 



Same + 10 parts per million salicylic aldehyde. 

 Same -j- 25 parts per million salicylic aldehyde.. 

 Same + 50 parts per million salicylic aldehyde.. 

 Same + 100 parts per million salicylic aldehyde 

 Same + 200 parts per million salicylic aldehyde 



Green 



Relative 



weight. 



growth. 



Otrams. 





1.35 



100 



1.35 



100 



.70 



51 



.35 



26 



.20 



15 



.15 



11 



The figures in the table show that salicylic aldehyde in amounts of 

 10 parts per million did not affect the green weight. The green 

 weight was the same in that culture as in the nutrient solution which 

 did not contain aldehyde. The culture containing 25 parts per mil- 

 lion of the aldehyde, however, produced a much smaller plant thari 

 the control. The growth was reduced from 100 to 51. Solutions 

 containing 50, 100, and 200 parts per million produced very poor 

 plants. The plants made very little growth and were almost dead 

 when the experiment was discontinued. 



EFFECT ON CABBAGE. 



An experiment in nutrient solution was made to determine the 

 effect of the salicylic aldehyde on young cabbage plants. The 

 nutrient solution was the same as that used with corn and cowpeas. 

 The salicylic aldehyde was used in quantities varying from 10 to 200 

 parts per million. In each culture 10 young cabbage seedlings were 

 grown. The plants were supported in the culture jar by means of a 

 cork, similar to the manner in which the wheat seedlings were grown. 

 The plants grew in the solution from May 25 to June 12, 1912. A 



