Study of Allelopathic Activity of Common Sowthistle Weed (Sonchus oleraceus L.)

Abstract

The present work was conducted to study the allelopathic activity of Common Sowthistle weed (Sonchusoleraceus L.) belongs to family Asteraceae growing in agricultural fields in Benghazi using Radish(Raphanus sativus L.) as test plant. Flowers, leaves, stems and roots aqueous extracts of Sonchusoleraceus L. at 1%,5% and 10% concentrations were applied to determine their effect on seedgermination, germination index (GI), speed/rate of germination (SG/RG), seedling vigor index (SVI), rootlength (RL), hypocotyle length (HL), seedlings fresh weight (FW) and seedlings dry weight (DW) of Radishunder laboratory conditions. The aqueous extracts of all plant parts caused inhibitory effects on allmeasurement, which increased progressively on increasing the concentration of extracts. On the otherhand, at low concentration (1%) stimulation of some traits of different plant parts was recorded. Theseresults could be explained in the light of the facts that a higher plants release a diversity ofallelochemicals into the environment, which include phenolics, alkaloids, long-chain fatty acids,terpenoids, and flavanoids. The compounds exhibit a wide range of mechanisms of action effect on DNA(alkaloids), photosynthic and mitochondrial function (quinines), phytohorme activity, ion uptake andwater balance (phenolics).