Assessment of allelopathic effect of St. John's wort (Hypericum perforatum L.) on lettuce

Cilj rada bio je procijeniti alelopatski utjecaj gospine trave (Hypericum perforatum L.) na klijavost i početni rast salate. U laboratoriju u Petrijevim zdjelicama istraţen je utjecaj vodenih ekstrakata od suhe mase stabljike i lista gospine trave. Vodeni ekstrakti od stabljike i lista gospine trave značajno su smanjili klijavost sjemena salate za 12% odnosno 11,1%. Na duljinu korijena klijanaca negativan utjecaj imao je samo ekstrakt lista, dok je ekstrakt stabljike pozitivno djelovao na duljinu izdanka salate za 19,6%. Svjeţa masa klijanaca smanjena je značajno u oba tretmana do 40,3%. Ekstrakt lista pokazali su veći inhibitorni utjecaj na duljinu korijena i izdanka i svjeţu masu klijanaca salate.The aim of the study was to evaluate the allelopathic effect of St. John’s wort (Hypericum perforatum L.) on germination and initial growth of lettuce. The influence of water extracts from the dry biomass of stems and leaves of St. John’s wort was investigated in Petri dishes in laboratory assay. Water extracts from stem and leaf of St. John’s wort significantly reduced seed germination of lettuce by 12% and 11.1% respectively. Only leaf extract had negative effect on root length of seedlings, while stem extract had a positive effect on the lettuce shoot length by 19.6%. Fresh weight of the seedlings was significantly decreased in both treatments up to 40.3%. The leaf extract showed a greater inhibitory effect on the root and shoot length and the fresh weight of lettuce seedlings