700 



J. P. Nitsch and C. Nitsch 



LOG. 



-6 

 MOLAR 



-5 -4 -3 



CONCENTRATION 



Fig. 8. Synergistic effects of chloiogenic acid (Ch), carteic acid (Ca), quinic acid 

 (Q), and caffeic + quinic acids at equimolar concentrations (Ca -|- Q) upon the 

 elongation of Avena first internodes. The concentration of lAA was 10 fig/h initial 

 length 4 mm. 



and transferred to tubes containing lAA only. An enhancement of 

 the lAA effect could be observed under these conditions. Such a re- 

 sult may perhaps be ascribed to the reported inhibitory effect of 

 chlorogenic acid on lAA oxidase (33). 



Carboxylic Acids 



Since the fraction containing the TJF Avas acid, the two most 

 prominent acids of tomato juice, malic and citric acid, were tested 

 on tissue cultures. The effect was slight (Table 2). 



Amino Acids 



Tomato juice contains, of course, many amino acids, such as 

 glutamic acid, glutamine, arginine, tryptophane (2), y-aminobutyric 

 acid (38), etc. It has been shown (28) that glutamic acid and gluta- 

 mine have a stimulatory effect upon the growth of Jerusalem artichoke 

 tissue cultures in the presence of lAA. A mixture of amino acids, such 



