Action-concentration curves 



Figure 1. The course of the theoretical 

 cojicentratioti-action curve of lAA 

 compared with the experirnetUal data 

 (°). Abscissa: log of the per cent 

 concentration. Ordinate: percentage 

 change of length of the test plant 

 (Avena coleoptile). 



log concn 



cc -nophfhy/acef/c acid 



og concn. 



Figure 2. The course of the theoretical 

 concentration-action curve of (x-naphtfvyl- 

 acetic acid compared with the experimental 

 data (o). Abscissa and ordinate as in 

 Figure 1. 



Figure 3. The course of the theoretical 

 concentration-action curve of eosine com- 

 pared with the experimental data (»). 

 Abscissa and ordinate as in Figure 1. 



og concn. 



161 



