Prospecção fitoquímica de adubos verdes em cultivo exclusivo e consorciado

Abstract

The preliminary phytochemical screening is the initial step in the identification of the main chemical groups of secondary metabolites in which belong allelopathic substances, serving as base for subsequent chromatographic analysis. This study aimed to characterize chemical groups of secondary metabolites present in green manures used as cover plants for weed control. Fifteen ethanolic extracts were obtained from leguminous species sunn hemp (Crotalaria anagyroides H.B.K.), jack beans (Canavalia ensiformis (L.) DC), pigeon pea (Cajanus cajan (L.) Millsp) and the grassy species black oat (Avena strigosa Schieb), sorghum (Sorghum bicolor (L.) Moench) and millet (Pennisetum glaucum (L.) R. Brown), sown with and without intercropping. Qualitative analytical tests were performed with these extracts, using specific reagents for the characterization of the major groups of plant substances. Coumarins derivatives and saponins are found in residues of all studied species of green manure, with and without intercropping. Polysaccharides and catechins, are absent in the residues of all species of green manures studied, with and without intercropping.