Evolution of Flavonoids in Embryobionta

Abstract

Flavonoids are traditionally considered good systematic markers since they occur in essentially all vascular plants, exhibit great structural diversity and are under genetic control. From the purely technical point of view it is also of importance that they are chemically stable and reasonably easy to isolate and to identify. Bate-Smith (1962) has already suggested that the first advantage to be gained from following up the implication of their systematic distribution would be the production of a natural or phylogenetic system depending not only on the outward and visible manifestations of the metabolic equipment in the plant, the exomorphic characters, but also on the metabolic equipment itself. Since 1962 enormous progress has been made in characterizing new flavonoids, in determining biosynthetic relationships and in mapping the natural distribution of both known and novel flavonoids. As a result, according to Harborne (1977c), the outstanding investigator in the latter field, Bate-Smith’s predictions have been amply fulfilled and an evolutionary scheme for the flavonoids is now within our grasp. Indeed, by listing primitive against advanced states of flavonoid evolution, Harborne hopes to have shown the predictive value of flavonoids to be considerable and that, through future work, the determination of the flavonoid profile of a given plant taxon should help in placing it correctly in a natural phylogenetic sequence.