Seed Fatty Acids, «Front-End»-Desaturases and Chemotaxonomy — a Case Study in the Ranunculaceae

Abstract

In many plants the seed lipid composition differs from that of the lipids in photosynthetic tissue. Unusual fatty acids are often present in the seed fat, but absent in leaves and other parts of the plant. The presence or absence of chemotaxonomically significant fatty acids can provide clues to a closer or less close relationship between plant species, genera or families. The chemotaxonomic significance of a number of unusual fatty acids is discussed by way of examples from different plant families. Particularly interesting is the situation in the family Ranunculaceae, which is considered to be a rather primitive plant family by many botanists. Gas chromatographic «fingerprints » indicate a large number of unusual fatty acids in seed lipids from this plant family. These unusual fatty acid patterns are highly characteristic. A number of Δ5- and Δ6-fatty acids were found only in one genus or in a few closely related genera. Other unusual fatty acids were typical for other genera.