INTRODUCTION TO BIOCHEMICAL SYSTEMATICS 4/ 



Kew Bulletin, used the term "comparative phytochemistry" which 

 he defined as "the knowledge of the connection between the natural 

 relationship of plants and their chemical composition." Greshoff ad- 

 vocated the use of a short chemical description as a part of the for- 

 mal description of a new genus or species. This is none other than 

 the "biochemical profile" which Alston and Turner suggested re- 

 cently (1959). 



As early as 1925 Munkner indicated full appreciation but pre- 

 mature optimism concerning the use of chemical data in the solution 

 of phylogenetic problems when he noted that in the "older" sys- 

 tematics morphological characters alone, and later anatomical charac- 

 ters, served to relate plants, while in "recent" time comparative chem- 

 istry was being utilized in the determination of phylogenetic 

 relationships. 



It is reasonable to ask why, in the hght of these early 

 recognitions of the potential role of biochemistry, so little progress 

 has been made. The question, of course, does not have a single answer, 

 but the lack of progress in biochemical systematics may be explained 

 partly through the developing interest in genetics and enzymology 

 around the turn of the century. These fields may have lured some 

 investigators who possibly would have turned to biochemical sys- 

 tematics. 



Also, many of the early surveys of natural products were in- 

 stigated from the more practical pharmacological approach. Biologists 

 of fifty years ago were not generally cognizant of the relationship of 

 chemistry to biology, and the biologist was, therefore, not likely to be 

 trained in chemistry. If present circumstances reflect persistent view- 

 points, the systematic botanists must have been even repelled by 

 chemistry. 



Until recently, techniques have not been available to yield 

 the refined chemical information necessary for biochemical systematics 

 to contribute greatly to systematics. A long and distinguished period 

 of survey has provided vast amounts of information concerning the 

 distribution of chemical substances among the plant species, and in 

 some instances this has proved helpful, usually in a corroborative way 

 to morphology, in systematics. Only in the last decade have techniques 

 such as chromatography allowed the study of microquantities of sub- 

 stances from individual plants. The application of chemistry to in- 

 dividual plants has provided almost unlimited opportunity. Of para- 

 mount importance is the fact that it allows the study of populations 

 —natural and otherwise. It allows biochemical systematics to become 

 experimental. Among lower taxonomic categories it often may allow 

 the natural affinity of phylogeny and genetics to be expressed through 



