Extraction and Measurement Techniques 25 



0D5 0.1 0.15 



CONC. OF AUXIN 



0.20 0.25 0.3MG/L 



24 MG/L 



CONC. OF AUXIN 



Fig. 11. A. Results of an Avena test showing the Hnear response to varying con- 

 centrations of auxin, indoleacetic acid (Went and Thimann, 1937, p. 41). B. Results 

 of an Avena test showing the lack of a quantitative response for concentrations of 

 auxin (indoleacetic acid) higher than optimum (Went and Thimann, 1937, p. 41). 



