Allelopathic Effects of Aqueous and Ethanolic Leaves Extracts of Schinus molle L. under Different Kinds of Pruning

Secondary metabolites produced by plants can be used in popular medicine, as well they can interact with plants and other organisms, in which case they are called allelochemicals and influence the neighboring ecosystem. This work aimed to evaluate the allelopathic effects of Schinus molle L. species widely used in reforestation and urban afforestation. Therefore, leaves of S. Molle were collected from different populations located at Alfenas and Nepomuceno in Minas Gerais, Brazil. Cypselae of lettuce (Lactuca sativa L.) were germinated in biochemical oxygen demand (BOD) chamber at 25 °C with a photoperiod of 12 h under different extracts concentrations. The experiment was performed in factorial design (2 × 4) with two kinds of extracts (aqueous and ethanol) and four concentrations (2.5, 5, 10 and 20 mg/mL) in randomized blocks. The variables analyzed were germination (%), germination speed index (GSI), % of normal seedlings, root length, fresh biomass and dry biomass. Changes in the cell cycle in meristematic cells of the used model were also evaluated. Concentration-dependent effect on all parameters was observed, with the exception of dry biomass exposed to ethanol extract. The root elongation parameter was different between the extracts even in lower concentrations, thus indicating that this is the most sensitive parameter of this species. Toxic effect from S. molle extracts was observed in all parameters regardless the kind of pruning management or method of extraction (water or ethanol).