PHENOLIC SUBSTANCES 203 



color had been completed, and Scott- Moncrieff in reviewing this work 

 outlined several generalizations concerning the inheritance of antho- 

 cyanins, such as the fact that the more oxidized form was usually 

 dominant to the less oxidized, and that 3-5 diglycosidic and acylated 

 anthocyanins were dominant to the 3 monoglycosidic and non- 

 acylated forms, respectively (Scott-Moncrieff, 1936). 



Beale et al. (1941) in another important review of the subject 

 concurred in general with the findings of Scott-Moncrieff. The num- 

 ber of species which had at that time been investigated was surpris- 

 ingly large though most of the work suffered from limitations of the 

 techniques then available. Between 1941 and the early 1950's rela- 

 tively little additional work on the inheritance of flower color was re- 

 ported. Haldane (1954), who apparently had interested Scott-Moncrieff 

 in the subject, outlined some of the problems which remained un- 

 solved at the time and deplored the declining interest in the study of 

 the biochemical genetics of flower color. Yet, even then a number of 

 important studies along these lines were in progress. Apparently, re- 

 newed interest stemmed in part from the introduction of paper 

 chromatographic techniques. Before such techniques appeared, it was 

 almost impossible to resolve the anthocyanins, yet complex mixtures 

 of pigments were frequently encountered. The first report of the use 

 of paper chromatography in the study of anthocyanins was that of 

 Bate-Smith (1948), and most, if not all, of the major biochemical- 

 genetic work on anthocyanins since has been facilitated by paper 

 chromatographic investigations. Several significant publications on 

 the inheritance of flower color have appeared in recent years, yet 

 these have not answered some of the basic questions of flavonoid bio- 

 synthesis which now center on interconversions of classes of flavo- 

 noids, the point at which substitutions in the A and B rings occur, and 

 the exact mode of union of the A and B units of the flavonoid nucleus. 

 Some consideration will be given to these points later. 



The extent of genetic investigations of flower color is empha- 

 sized by the work of Paris et al. (1960) who surveyed publications 

 treating the inheritance of flower color in seventy-five different species. 

 These workers attempted the formulation of a general inheritance 

 scheme governing flower color. They recognized six major analogous 

 genes on the basis of the frequency of appearance of the correspond- 

 ing phenotypic effect. While it is unquestionably desirable to attempt 

 to develop an integrated system of genetic notation in which factors 

 known to have equivalent biochemical expression are assigned the 

 same symbol, it is doubtful that the arbitrary recognition by these 

 authors of six types of analogous genes based entirely on the pheno- 

 typic expression of color alone is a positive contribution. Rather, it 



