New Auxins From 'Maryland Mammoth' Tobacco 65 



The possibility that the growth-promoting substances isolated 

 from 'Maryland Mammoth' tobacco are artifacts cannot yet be ex- 

 cluded. The extensive work of Chibnall et al. (4) and others has shown 

 that long-chain alcohols occur widely in both the cuticle and cellular 

 waxes of plants (12) , although the wax of tobacco was found to be 

 associated primarily with the cell (4). The occurrence of a great va- 

 riety of unsaturated fatty acids in plant tissues also is well established. 

 However, these two types of substances are interesting in their own 

 right. The comparatively narrow range of activity in the series of 

 long-chain alcohols is noteworthy, since there exists very little differ- 

 ence in solubility, chemical reactivity, and other physical and chemi- 

 cal properties between the inactive l-hexadecanol and the active 1- 

 octadecanol. 



The physiological effects of long-chain fatty acids have been re- 

 ported previously by several workers. Haagen-Smit and Viglierchio (6) 

 found that several of these compounds, such as myristic acid and 

 linoleic acid, were active in the Wehnelt bean test for wound hor- 

 mones. Stowe (8) reported that several long-chain fatty esters, includ- 

 ing a preparation isolated from 'Alaska' peas, were active in stimu- 

 lating growth in pea epicotyl sections, although they were inactive 

 on oat coleoptiles. However, the degree of activity of the tobacco iso- 

 late is unusual and suggests that it may possess peculiar structural 

 features not now appreciated as being important to growth-regulatory 

 activity. 



The importance of long-chain unsaturated fatty acids such as lino- 

 lenic acid, arachidonic acid, and docosahexaenoic acid in animal nutri- 

 tion is becoming increasingly evident upon continued investigation. 

 In recent months, two similar compounds important to the lives of 

 insects have been reported: Butenandt et al. (2) have shown that the 

 sexual attractant of the silk worm (Bombyx mori) is the unsaturated, 

 primary alcohol 10,12-hexadecadiene-l-ol, while the active constituent 

 of the royal jelly of the honey bee has been identified as 10-hydroxy- 

 decenoic acid (3). The results of the investigation of 'Maryland Mam- 

 moth' tobacco strongly indicate that this type of compound may prove 

 to hold an equally important place in the plant world. 



SUMMARY 



A paper-chromatographic study of growth-promoting substances 

 from 'Maryland Mammoth' tobacco (Nicotiana tabacum L.) revealed 

 the presence of two compounds which, although they exhibited chro- 

 matographic behavior similar to that of indole-3-acetic acid and in- 

 dole-3-acetonitrile, were found to be nonindolic. Isolation and char- 

 acterization provided evidence that one active material consisted 



