The in vitro investigation of phytotoxic activity on germination and seedling development is the initial part in the search for new herbicides or bioerbicides, when verifying this action new in vivo ...studies must be carried out on weeds. In this way, the phytotoxic action of Hyptis suaveolens was investigated on the initial development of two economically important species, lettuce (Lactuca sativa L.) and soybean (Glycine max L.) Initially the crude ethanolic extract from the leaves of H. suaveolens was obtained, which was partitioned into a separating funnel, using one part water to four ethyl acetate (4x), obtaining the aqueous and organic fraction. The parameters analyzed were: germination inhibition, germination speed index, growth inhibition of seedlings and biomass production. The organic fraction inhibited 100% germination of lettuce seeds at all concentrations and, for soybean, it was observed that the highest inhibition was 33% at the highest concentration. In the test using the aqueous fraction, the inhibitions of the germination of the soybean seeds occurred from the concentration of 5%. The germination rate of lettuce and soybean seeds was also reduced by the two fractions. The other parameters were also negatively affected. Thus, it was concluded that the aqueous and organic fractions present phytotoxic potential in the development of lettuce and soybean.
Em função da interferência do milho em outras plantas, objetivou-se verificar a presença e a concentração de benzoxazolinona no milho por meio de extração aquosa obtida de material vegetal das ...cultivares AG-1051, C-333 e C-435. A massa fresca das amostras foi colocada em água destilada e deixada em repouso durante quatro horas. O extrato foi filtrado e particionado em solventes com diferentes polaridades. O extrato etéreo desidratado foi filtrado, concentrado em evaporador rotatório e levado à estufa. Este foi purificado por cromatografia de camada delgada. Recristalizou-se em hexano, e os cristais obtidos foram submetidos à análise em espectrometria no Infravermelho. As bandas presentes no produto padrão também foram caracterizadas nas amostras das cultivares de milho testadas. As amostras dos extratos foram qualificadas e quantificadas por espectrofotometria de ultravioleta. Pelos resultados, infere-se que a planta de milho possuiem seu metabolismo a benzoxazolinona, na seguinte ordem decrescente: AG-1051 29 mg g-1, C-333 24 mg g-1 e C-435 21 mg g-1 de BOA.Due to the interference of maize on other plants, the presence and concentration of benzoxazolinone in this particular plant (maize) wasdetermined via the aqueous extract of three varieties of maize (AG-1051, C-333 and C-435). The fresh sample material was allowed to stand in distilled water for four hours. The extract was filtered and partitioned with solvents of varying polarities. The dried etherextract was filtered, concentrated on a rotary evaporator and dried in an oven. The residue was purified by thin layer chromatography and recrystallized from hexane. The crystals were analyzed by infrared spectroscopy. The bands present in the spectrum of the referencesubstance were also observed in the spectra of the samples obtained from the three varieties of maize studied. The extract samples were characterized and quantified by UV spectroscopy. The results indicated that the three varieties of maize possessed benzoxazolinone in their metabolism in the decreasing order AG-1051 29 mg g-1 > C-33324 mg g-1 > C-435 21 mg g-1 of BOA.
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