Preliminary report on the allelopathic potential of South American Imperata species (Poaceae: Andropogoneae)

Background: A significant number of species of grasses (Poaceae) have allelopathic properties and two genera of Andropogoneae -Cymbopogon and Bothriochloa- are the main aromatic genera recognized in the family. The genus Imperata (Poaceae: Andropogoneae) is widely distributed, with several species being present around the world. Questions and / or Hypotheses: This study assessed the allelopathic potential of some South American species of Imperata taking into account previous reports on I. cylindrica, which has been extensively studied due to its invasiveness and allelopathic potential. Studied species / data description /Mathematical model: I. brasiliensis, I. condensata, I. minutiflora, and I. tenuis Study site and dates: Greenhouse of the Instituto Multidisciplinario de Biología Vegetal, Sistemática y Filogeografía de Plantas, Córdoba, Argentina. Methods: We obtain the aqueous extract from the studied species and we evaluated its effect on germination and root and shoot growth of lettuce, corn, and tomato. Results: In bioassays, aqueous leaf extract of I. brasiliensis, I. condensata, I. minutiflora, and I. tenuis inhibited seed germination and root and shoot growth of lettuce (Lactuca sativa), tomato (Solanum lycopersicum), and maize (Zea mays). The extracts mainly affected root and shoot length, whereas the effect on seed germination was low. Conclusions: The studied species may contain allelochemicals, which interfere with seed germination and seedling growth. Future research on the type of chemical compounds present in aqueous extracts may contribute to their use for agroecological purposes.