92 



BOTANICAL GAZETTE 



[FEBRUARY 



Heliotropiiij or piperonal, is the aldehyde of piperonylic acid. It 

 possesses the pleasant odor of heliotrope. The growth of wheat plants 

 in solutions was markedly afFected by the presence of heliotropin. 

 Although the plants w^ere not killed by a concentration of looo ppm. 

 or lesSj they were injured by such slight quantities as i ppm. It is 

 worthy of remark that the tops of the wheat plants were more affected 

 by the heliotropin than the roots. The roots were healthy and of 

 nearly equal development in all solutions of heliotropin used. 









-'-■ -'■!-".> 



..-.J^- 



i-f 



^,,.i-^^,-; ^. ^.; 





-^. 



i' 









i^i'j'ffM'- ■^;'"^'' ■-■'■■"■- ■^■■" '-''' ■ \ V ■ ■'■"■"'-^'■-''i'^-^'iz 



Fig. 7 



MISCELLANEOUS COMPOUNDS 



lo not permit 

 These bodies 



erf classification with the majority of compounds used. 

 are skatol, ricin, mucin, and quinic acid. 



In solutions skatol proved to be somewhat toxic to wheat plants. 

 A concentration of 200 ppm. was sufficient to kill seedling plants in 

 nine days, and in the same time a concentration of 50 ppm. was 



ef!ect. the 



mj uncus 



those cases where skatol had a harmful 

 >Ian 



pnnci 



