Allelopathic activity of broom (Scoparia dulcis L.) on the germination of invasive plants.
Allelopathy is characterized by effects on plant germination or development caused by chemicals released by other plants. This work aimed to verify the allelopathic activity of Scoparia dulcis leaves and roots in weeds and lettuce, as well as to determine the phenolic compounds present in the studied plant. The experiment was arranged in a 2 × 5 factorial design, with six replications of 15 seeds each. The seeds were placed to germinate in agar layers, and after ten days were evaluated the germination percentage, shoot length and root primary length. Phytochemical analysis using high performance liquid chromatography was also carried out, in which the samples were injected three times in the chromatographic system to obtain the average concentrations and retention times, allowing to identify and quantify the studied metabolites. The results showed that this species has allelopathic potential, as it interfered in the development of all receiving plants studied, and the inhibitory action exerted by the leaves was more significant/ou intense on the analyzed variables. On the other hand, the roots presented a larger total amount of phenolic compounds, being caffeic acid found in greater amount both in the roots and leaves.