ALLELOPATHIC EFFECTS OF Cyperus rotundus L. AND Cynodan dactylon L. ON GERMINATION AND GROWTH RESPONSES OF LETTUCE (Lactuca sativa)

Abstract

This study was conducted to investigate the allopathic effects of Cyperus rotundus and Cynodan dactylon (L.) extracts on seed germination and seedling growth characters of lettuce (Lactuca sativa). Four concentrations (5, 10, 15 and 20 %) of whole plant aqueous extracts of both weeds were tested for assessing their allelopathic effect on seed germination and seedling growth of Rapido 344 lettuce variety. This study was conducted at Biology Laboratory of Uva Wellassa University, Sri Lanka in 2014 and experimental units were petri dishes in depths and diameters of 2 and 5 cm, respectively. The shoot and root length, dry weight, germination percentage were measured. The experimental results revealed that all the concentrations of both the weed extracts had inhibition effect on germination percentage, shoot & root length and dry weight of lettuce. The inhibitory effect of the extracts was concentration dependent. However, at 5% of C. dactylon extract did not significantly affect on seed germination and growth of seedlings. The highest degree of growth inhibition was observed in 20 % of both weed extracts.