Monomer composition of polysaccharides of seed cell walls and the taxonomyof the Vochysiaceae

The distribution of polysaccharides from the seed cell walls of 57 samples of Vochysiaceae native to Brazil were studied, comprising 16 species distri buted among the genera Callisthene, Qualea, Salvertia and Vochysia. The pol ysaccharides were extracted with hot water, then hydrolyzed with the result ing monomers analyzed by HPLC. All samples yielded arabinose, galactose, gl ucose, mannose and rhamnose, the relative amounts of each monomer, however, varying from one sample to another. Arabinose was always the predominant c omponent, which implies that it might possibly be used as a marker of the V ochysiaceae. The quantitative distribution of monosaccharides was similar b etween the species of Qualea and Callisthene, characterized by the predomin ance of arabinose and mannose, and between the species of Salvertia and Voc hysia, which contained higher amounts of arabinose and galactose. Such resu lts are consistent with affinities inferred from floral morphology, wood an atomy and molecular data. Substantial intraspecific variation was observed for some species. UPGMA analysis based on the distribution of the monosacch arides reveals two main clusters, according to the links commented above. T he resultant phenogram is not coherent with the current sectional classific ation of the Vochysiaceae, but the differences in the monosaccharides distr ibution between the two clusters are strongly supported by ANOVA. (C) 2000 Elsevier Science Ltd. All rights reserved.