Distribution of seed fatty acids and the taxonomy of Vochysiaceae

Abstract

The distribution of seed fatty acids of 16 species of Vochysiaceae native to Brazil, corresponding to the genera Callisthene, Qualea, Salvertia and Vochysia, and amounting to 57 samples, were studied. The methyl esters of the fatty acids were analyzed by GC–EIMS. For most species, fatty acid patterns are seemingly useful for species characterization. Intraspecific variability of samples of Salvertia grandiflora seems to have geographic significance. With one exception, palmitic and oleic acids predominate in the fatty acids distribution of Qualea and Callisthene. Q. grandiflora possesses exceptional amounts of lauric acid. Relatively high amounts of either C20–C22 (saturated or monounsaturated) or stearic acids characterize Salvertia and Vochysia. UPGMA analysis of fatty acids distribution based on Euclidean distances resulted in a cluster combining Callisthene and all samples of Qualea, except Q. grandiflora. Samples of Vochysia are combined into several clusters. The dendrogram is suggestive of taxonomic relationships, allowing the distinction of taxa down to the sub-sectional level. V. pyramidalis, from section Ciliantha, subsection Ferrugineae, has closer chemical affinities with species of section Vochysiella, subsection Decorticantes. Comparing with monomers of polysaccharide seed cell walls of Vochysiaceae, fatty acid patterns revealed lower intraspecific variability and higher taxonomic resolution.