Abstract

Weed plants having strong allelopathic potential provide themselves with a competitive advantage in crop fields through the release of allelochemicals. Fimbristylis dichotoma, a well-known weed, was taken in the present study to evaluate its allelopathic potentiality under laboratory condition. Aqueous methanol extracts of dried F. dichotoma were applied on the seedling growth of four dicotyledonous [cress (Lepidum sativum L.), lettuce (Lactuca sativa L.), alfalfa (Medicago sativa L.) and rapeseed (Brassica napus L.)], and four monocotyledonous [Italian ryegrass (Lolium multiflorum Lam.), barnyard grass (Echinochloa crus-galli L.), timothy (Phleum pratense L.) and sand fescue (Festuca megalura Nutt.)] at four concentrations 0.01, 0.03, 0.1 and 0.3 g dry weight (DW) equivalent extract/ml. The seedling growth of all test plant species experienced an inhibition in all concentrations by the extracts of F. dichotoma and the inhibition was concentration-dependent. A complete inhibition of lettuce seedling was found at 0.1 g DW equivalent extract/ml and also the seedling growth of cress, lettuce, alfalfa and sand fescue was inhibited completely at the concentration of 0.3 g DW equivalent extract/ml. Considering concentrations required for 50% growth inhibition shoot of alfalfa and root of lettuce showed most sensitivity to the extract of F. dichotoma. These results imply that Fimbristylis dichotoma may have allelopathic properties and may contain allelochemicals which may exert deleterious effect to its surrounding environment.