Stimulation of Auxin Action by Lipides 427 



tissues which they believe interacts with auxin. In pea sections them- 

 selves, Christiansen and Thimann (3) noted that lipide utilization 

 paralleled auxin-induced growth, and that the same inhibitors which 

 reduced the cell elongation also slowed the lipide decrease. 



Antedating these reports is the work of English et al. (8) on wound 

 hormones which has been further delineated by Haagen-Smit and 

 Viglierchio (10). Although the wound hormones problem must 

 have some relationship to the present work, inasmuch as in both 

 cases trace quantities of lipides potentiate a hormonal response, 

 there are some striking unexplained differences in the specificity of 

 the two systems. To begin with, traumatic acid has no influence 

 on pea section growth. Next, the most effective substances for wound 

 tissue proliferation were found to include lauric, myristic, and linoleic 

 acids, none of which stimulates epicotyl section elongation. Lastly, 

 cytochrome-c, coenzyme A, and ascorbic acid all increase the wound 

 hormone response whereas all had no influence on the peas (17). 

 There is thus some fundamental divergence in the operation of the 

 two hormonal systems. Unfortunately, none of the compounds now 

 shown to be active in accelerating pea section growth was tested by 

 the above workers on their material. 



Lipoidal compounds have been linked to auxin action by several 

 workers using several plant systems. Although the mechanisms behind 

 these systems may not be identical, further analysis of these auxin- 

 lipide interactions should prove fruitful for our understanding of 

 hormonal regulation in plants. 



ACKNOWLEDGMENT 



This investigation was assisted by Grant G2828 from the National 

 Science Foundation, to Professors K. V. Thimann and R. H. Wetmore. 

 Professor Thimann's interest in this work is deeply appreciated, as is 

 the expert technical aid of Mrs. Irmgard W. Kurland. 



LITERATURE CITED 



1. Brian, P. ^V., and Hemming, H. G. Complementary action of gibberellic acid 

 and auxins in pea internode extension. Ann. Bot. II. 22: 1-17. 1958. 



2. Busse, M. Uber die Wirkungen von Kobalt auf Stieckung, Atmung, und 

 Substanzeinbau in die Zellwand bei Avenakoleoptilen. Planta. 53: 25-44. 

 1959. 



3. Christiansen, G. S., and Thimann, K. V. The metabolism of stem tissue dur- 

 ing growth and its inhibition. II. Respiration and ether-soluble material. 

 Arch. Biochem. 26: 248-259. 1950. 



4 Crane, F. L. Internal distribution of coenzyme Q in higher plants. Plant 



Physiol. 34: 128-131. 1959. 



5. Crawford, R. B., Morrison, M., and Stotz, E. Studies on the role of lipides in 



mammalian cytochrome c reductase. Biochim. Biophys. Acta. 33: 543-550. 1959. 



