XVI International Botanical Congess

Melinis minutiflora Beauv., a C4 forage grass, is widesperead in cerrado areas, displacing some native herbaceous species. Light availability seemed to be the most important factor related to its distribution and abundance. Echinolaena inflexa (Poir.) Chase is a C3 native species with high biomass production, which favours sits distribution comparable to m. minutiflora. In the present study, sugars form both species were analyzed, correlating carbohydrate metabolism with their distribution and phenology. During vegetative growth, no differences in sugar levels were observed in aerial parts of both species. However, expressive increase in sugars, mostly sucrose, was found in m. minutiflora stems during eh reproductive phase. E. inflexa showed no differences in sugar levels, but only in composition. Low molecular weight sugars predominated in leaf blades, sheaths and stems of this species, with different homologous series of oligosacharides characterizing the leaf blades. Supported by FAPESP, CAPES, CNPq