Herbicidal potential of Araucaria angustifolia (Bertoloni) Otto Kuntze in lettuce seedlings in vitro

Resumen

Araucaria angustifolia (Bertoloni) Otto Kuntze plants are a viable source of potentially active secondary metabolites; however, deep studies and researches about the activity of these compounds are needed. The objective of this work was to assess the herbicidal activity of ethanolic extracts of plants of the species A. angustifolia in lettuce seedlings in vitro. Ethanolic extracts at different concentrations (0,0%, 12.5%, 25.0%, 50.0%, and 100.0%) were prepared using barks and leaves. A semisolid MS medium with pH adjusted to approximately 5.7 was prepared, solidified with 8g L-1 of agar, and autoclaved at 1.6atm for 20 minutes. The extracts were added to the culture medium during their preparation before the autoclaving, using an automatic pipette containing 0.1mL of A. angustifolia extract per lettuce seedling. The number of leaves per seedling, seedling height, chlorophyll content, root and shoot dry weights, and mortality percentage was determined at 20 days after inoculation. The results showed that the extract from leaves or barks of A. angustifolia plants has herbicidal activity in lettuce seedlings in vitro, and the extract concentration of 100% presented the best inhibitory results for the variables evaluated.