Groiuth Factors in Tomato Fruit 699 



elongation of coleoptile sections. Another might be ferulic acid which 

 was reported by Akkerman and Veldstra (1) as being one of the com- 

 ponents of Kockemann's blastocholine. In our tests, ferulic acid had 

 an inhibitory effect upon the growth of the first internodes of Avena 

 seedlings in the presence of small amounts of lAA. Upon the growth 

 of Jerusalem artichoke tissues, however, ferulic acid had no visible 

 effect, at least at concentrations ranging from lO-e to lO-^ M. Ferulic 

 acid, on the other hand, has been reported by Hemberg (7) and by 

 Reinders-Gouwentak and Smeets (35) to have a synergistic effect with 



auxins. 



Water-soluble inhibitors. The aqueous fraction was the one which 

 contained the most powerful inhibitors after autoclaving. Their 

 chemical nature has not yet been determined. 



Chlorogenic Acid and Its Derivatives 



In addition to ferulic acid, Akkerman and Veldstra (1) extracted 

 caffeic acid from tomatoes and claimed that it was a component of 

 the blastocholine complex. Later on, however, it was reported (7, 35) 

 that caffeic acid not only was not an inhibitor but was actually an 

 auxin synergist. In our tests with Jerusalem artichoke tissues, caffeic 

 acid (at least between lO^ and 10 ^ M) gave a small synergistic effect 

 with lAA. Since caffeic acid is actually a component of chlorogenic 

 acid, which has been reported in tomatoes (8), we have also tested 

 chlorogenic acid^, quinic acid, a mixture of caffeic and quinic acids, 

 and cynarine^ which contains two molecules of caffeic acid per mole- 

 cule of quinic acid (32). None of these compounds gave evidence for 

 a stimulation of growth at greater than 10 to 15 per cent concentra- 

 tions ranging from lO-s to 10-* M. Toxic effects occurred at higher 

 concentrations. 



On the contrary, quite unexpected results were obtained when 

 these compounds were tested on the Avena first internode and coleop- 

 tile bioassays for auxins. None of them had any auxin activity when 

 used alone. In conjunction with low concentrations of lAA, however, 

 they showed a marked synergistic effect, a rather pronounced re- 

 sponse being obtained with chlorogenic acid (29). The effect of chloro- 

 genic acid could be ascribed to its caffeic acid moiety, the quinic acid 

 part having no growth-promoting effect (Figure 8). Similar results 

 were obtained with coleoptile sections. Chlorogenic acid had an ef- 

 fect even when it was not given at the same time as lAA to the first 

 internode or coleoptile sections. Thus, these sections could be first 

 soaked in chlorogenic acid for 1 hour, then taken out of this solution 



^Kindly supplied by Dr. A. C. Hulme. 

 * Kindly supplied by Dr. L. Panizzi. 



