The allelopathic activity of the leaf aqueous extract of guava (Psidium guajava L.) on seed germination and root growth in lettuce (Lactuca sativa L.) was studied in an experiment consisting of four replicates with 10 seeds each and extract concentrations of 5, 10, and 20%. Guava allelopathic activity occurred during the germination and growth of lettuce roots at 20% extract concentration, as shown by ANOVA. This result suggested the allelopathic potential of the species. Therefore, the success of P. guajava in invading environments could be partially due to allelopathy. Further studies using other plant parts and field experiments should be conducted.
Abandoned pastures; allelopathy; biological invasion; riparian vegetation; seeds
