Major constituents of the foliar epicuticular waxes of species from the Caatinga and Cerrado

The epicuticular waxes of leaves of four species (Aspidosperma pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) from the Caatinga, (a semi-arid ecosystem of Northeast Brazil) and four species (Aristolochia esp eranzae, Didymopanax vinosum, Strychnos pseudoquina and Tocoyena formosa) f rom the Cerrado, (a savanna ecosystem covering one third of the Brazilian t erritory), were analyzed. Six species contained a high content (above 60 mu g.cm(-2)) of wax, four of them from the Caatinga. Triterpenoids and n-alkan es were the most frequent and abundant constituents found in the species fr om both habitats. The distribution of n-alkanes predominated by homologues with 27, 29, 31 and 33 carbon atoms, displayed no consistent differences be tween species from the two habitats. Lupeol, beta -amyrin, epifriedelinol a nd ursolic acid were the triterpenoids found. Triterpenoids clearly predomi nate over alkanes in the waxes from the Cerrado species. The waxes of two e vergreen species from the Caatinga yielded n-alkanes as predominant constit uents. A comparison of foliar epicuticular waxes of native plants from ecos ystems with different hydric constraints is discussed.