Allelopathic effects of narcissus (Narcissus tazetta L.) extract on germination, growth and physiological characteristics of couch grass (Agropyron repens) and wild oat (Avena fatua)

This experiment was conducted to evaluate the allelopathic effects of bulb and leaf aqueous extracts of narcissus (Narcissus tazetta L.) on germination, growth and physiological characteristics of two weed species namely couch grass (Agropyron repens) and wild oat (Avena fatua). For this purpose, two seprate experiments were conducted in a completely randomized design with three replications in laboratory and greenhouse conditions in 2017. Treatments included three levels of leaf and bulb extracts (1, 2 and 3 % w/v) along with control (distilled water). The results showed that increasing the concentrations of leaf and bulb extracts reduced germination percentage and germination rate of the seeds, root length, plant height and chlorophyll content a, b and total of couch grass and wild oat, but total soluble sugars and antioxidant activity increased. The concentration of 3 % of the bulb extract reduced seed germination percentage, root length, plant height and total chlorophyll in couch grass by 81, 42, 38 and 49 %, and in wild oat by 63, 44, 36 and 40 % compared to the control plant, respectively. The results of this study showed that can be used the allelopathic effects of leaf and bulb extracts of narcissus in order to biological control of these two weeds.