Phytotoxicity Effect of Fennel Essential Oil on Germination and Growth Characteristics of Common Mallow and White Goosefoot

Continued use of herbicides has increased the resistance of weeds to them and also reduced the quality of soil and groundwater. Due to the herbicidal properties of plant essential oils, the aim of this study was to investigate the effect of fennel essential oil on seed germination and seedling growth of common mallow and white goosefoot in laboratory conditions, which was performed as a factorial in a completely randomized design in the research laboratory of the Cooperative Foundation of Rudan city, Hormozgan province, in 2016 . The essential oils were extracted from Fennel seeds by hydrodistillation by using a clevenger apparatus and were analyzed by GC and GC-MS. The results showed that the highest percentages of seeds essential oil components were related to e-anethole (66.92%), methyl chavicol (14.54%), fenchone (7.01%) and limonene (6.84%), respectively. Weed seeds after disinfection with sodium hypochlorite and then drying, exposed to concentrations of 0 (distilled water), 200, 400, 600, 800 and 1000 μl/l of fennel essential oil in suitable light conditions at 25 °C. Based on the results the Fennel essential oil reduced the percentage and speed of seed germination, root and shoot length of common mallow and white goosefoot. With increasing the concentration of essential oil, the percentage and speed of seed germination also decreased significantly. In general, the response of the studied weeds to fennel essential oil was different; In a way, the common mallow was more sensitive to white goosefoot. The greatest inhibitory effect on the germination of common mallow and white goosefoot seeds was related to the concentration of 1000 μl/l of essential oil, so that in the case of common mallow, germination stopped completely. Allelopathy index at a concentration of 1000 μl/l fennel essential oil for common mallow and white goosefoot was -1 and -0.83, respectively.According to the results, the use of 1000 μl/l fennel essential oil is recommended to control common mallow and white goosefoot.