SEARCH

SEARCH BY CITATION

Keywords:

  • Asteraceae;
  • underground organs;
  • fructans;
  • cerrado

SUMMARY

Underground organs of 35 herbaceous species of Asteraceae, representing 6 tribes, were collected from a restricted area of the Brazilian cerrado. Occurrence, histological location, concentration and composition of fructans were determined in thickened underground organs of 19 species in the tribes Eupatorieae, Heliantheae and Vernonieae. Spherocrystals of inulin were histologically detected in approximately 80 % of all species examined; these are distributed in the reserve parenchyma cells, particularly in the Vernonieae. In the Heliantheae and Eupatorieae they are found in the parenchyma, sometimes associated with vascular tissue. Total fructans as a proportion of dry mass range from 2.4 % in Vernonia brevifolia to 55% in Calea platylepis, regardless of the water contents of the storage organs. The highest degree of polymerization is observed in the Heliantheae. Thin-layer chromatography demonstrates that isokestose predominates throughout and that different proportions of fructo-oligosaccharides are present, depending on species.

The patterns of fructo-oligosaccharides are similar at generic and tribal levels, suggesting phylogenetic relationships within the Asteraceae.