Chromatographic Investigations of Indole Compounds 91 



All these results provide further evidence that, although the tis- 

 sues of different plants can often carry out the same degradation re- 

 actions, thus suggesting the presence of similar enzyme systems, these 

 enzymes can nevertheless show different behavior towards a specific 

 substrate. Studies of this type are of use in defining some of the bio- 

 chemical reactions which are important in plant metabolism and 

 which may be involved in the regulation of plant growth by synthetic 

 chemicals. 



LITERATURE CITED 



1. Andreae, W. A., and Good, N. E. The formation of indoleacetylaspartic acid 

 in pea seedlings. Plant Physiol. 30: 380-382. 1955. 



2. , and Good, N. E. Studies on 3-indoleacetic acid metabolism. IV. Con- 

 jugation with aspartic acid and ammonia as processes in the metabolism of 

 carboxylic acids. Plant Physiol. 32: 566-572. 1957. 



3. Fang, S. C., Thiesen, P., and Butts, J. S. Metabolic studies of applied indole- 

 acetic acid-I-C" in plant tissues as affected by light and 2,4-D treatment. Plant 

 Physiol. 34: 26-32. 1959. 



4. Fawcett, C. H., Ingram, J. M. A., and Wain, R. L. The /3-oxidation of w-phe- 

 noxyalkylcarboxylic acids in the flax plant in relation to their plant growth- 

 regulating activity. Proc. Roy. Soc. B. 142: 60-72. 1954. 



5. , Pascal, R. M., Pybus, M. B., Taylor, H. F., Wain, R. L., and Wight- 

 man, F. Plant growth-regulating activity in homologous series of w-phenoxyal- 

 kanecarboxylic acids and the influence of ring substitution on their break- 

 down by j8-oxidation within plant tissues. Proc. Roy. Soc. B. 150: 95-119. 1959. 



•6. , Taylor, H. F., Wain, R. L., and Wightman, F. The degradation of cer- 

 tain phenoxy acids, amides, and nitriles within plant tissues, pp. 187-194. hi: 

 R. L. Wain and F. Wightman (eds.), The Chemistry and Mode of Action of 

 Plant Growth Substances. Butterworth Sci. Publ., London. 1956. 



7. , Taylor, H. F., Wain, R. L., and Wightman, F. The metabolism of 



certain acids, amides and nitriles within plant tissues. Proc. Roy. Soc. B. 148: 

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8. Seeley, R. C, Fawcett, C. H., W^ain, R. L., and Wightman, F. Chromatographic 

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9. Wain, R. L., and Wightman, F. The growth-regulating activity of certain w- 

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10. Went, F. W., and Thimann, K. V. Phvtohormones. 294 pp. Macmillian Co. 

 New York. 1937. 



DISCUSSION 



Dr. Thimann: Your bioassay pictures appear to settle the ques- 

 tion as to whether indole-3-butyric and indole-3-caproic acids are 

 active per se or only on conversion to indole-3-acetic acid. They are 

 apparently active per se. Would you agree with that? There is clearly 

 more than one peak. 



Dr. Wightman: We have often discussed this question at Wye, par- 

 ticularly with regard to whether the activity of indole-3-butyric acid 



