Evaluation of physiological quality of lettuce and rocket salad seeds in the presence of purple nuts edget extract

Purple nuts edge (Cyperus rotundus L.) is responsible for great losses in crop production areas. Purple nuts edge tubers possess substances with allelopathic effects on certain crops. The aim of this study was to evaluate the physiological quality of lettuce and rocket salad seeds grown on different substrates in the presence of purple nuts edge extract. A completely randomized experimental design was used with a 3×5 factorial scheme (three substrates × five doses of purple nuts edge extract) and four replicates of 50 seeds. The extract was diluted to four different concentrations (25, 50, 75 and 100%), and distilled water was used as a control treatment (0%). Seeds were sown in three different substrates: Germitest paper, sand or soil. The first and second germination count, the total germination and the germination speed index were evaluated. Lettuce germination was affected by the application of purple nuts edge extract to the tested substrates. Lower germination percentages were observed for sand than for the remaining tested substrates. The application of purple nuts edge extract did not affect the evaluated germination parameters for rocket salad seeds. The germination of lettuce and rocket salad seeds was higher with soil as substrate. Key words: Lactuca sativa L., Eruca sativa L., Cyperus rotundus L.