Phytotoxicity of Hyptis Suaveolens against soybean and lettuce crops

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.