Protoanemonin 



Bacitracin 



\N-CI Phthalamic 



10 MG/L 



CONC. OF SYNERGIST 



Fig. 73. Synergistic effects of some substances with auxin in growth: A: effects of 

 various concentrations of protoanemonin and coumarin on the Avena straight growth 

 test; all solutions contained 1 mg./l. indoleacetic acid and 1% sucrose (Thimann 

 and Bonner, 1949). B: effects of various concentrations of chelidonic acid, bacitracin, 

 and N-chlorophthalamic acid on the pea straight growth test; all solutions contained 

 0.1 mg./l. indoleacetic acid (Leopold et al, 1952; Leopold and Guernsey, unpub- 

 lished). 



164 



