JOYCE A. BENTLEY 



Marine Laboratory 

 Aberdeen, Scotland 



Some InvestlgatLons on Interconvertible 

 Naturally Occurring Auxins 



Modern techniques in plant hormone analysis, in particular the use 

 of paper chromatography for the purification of extracts, followed by 

 bioassay, have revealed a number of as yet chemically unidentified 

 auxins in various plant species. This paper is concerned with one 

 particular group, which has come into prominence recently and about 

 which very little is known — that is, the group of so-called intercon- 

 vertible auxins. A group of three interconvertible auxins was first 

 reported in the ether-insoluble fraction of tomato roots (8), followed 

 by a report of similar substances in pea roots (1). The present investi- 

 gation deals with a group of interconvertible auxins located in vari- 

 ous species of algae. The algae were chosen as a field of investigation 

 for two reasons. Firstly, there is an ecological problem; there is con- 

 siderable evidence that the growth and distribution of both marine 

 and freshwater algae may be governed, at least in part, by minute 

 traces of metabolites in their aqueous environment; these metabo- 

 lites may range from toxins to vitamins and hormones (8, 9). It is of 

 interest to investigate whether the algae do in fact produce hormones 

 of the auxin type and excrete them to the media in which they are 

 growing. Secondly, the single-celled algae are free from the prob- 

 lems of differentiation encountered in the higher plants. Since the 

 auxins affect fundamental aspects of growth, for example cell elonga- 

 tion and cell division, their primary effect appears to be on the indi- 

 vidual cell, and it is therefore of interest to investigate their occur- 

 rence in single-celled organisms. 



MATERIALS 



The following materials have been examined. I am grateful to 

 the various people, indicated in the text, who generously supplied 

 material. 



[25] 



