Allelopathic activity of extracts from leaves of Ziziphus spina-christi collected in five Tunisian ecotypes

This work was performed to investigate the potential allelopathic effects of Ziziphus spina-christi aqueous extracts (AE) on the seed germination and seedling growth of Triticum durum L. and Raphanus sativus L. Plant materiel (leaves) were collected from five ecotypes (INRGREF, Dgeuche, Kebeli, Nafta and Tozeur) . Total phenolic and flavonoid contents have been done by Folin-Ciocalteu reagent and colorimetric assay respectively. The germination efficiency, plumule and radicule length of Triticum durum and Raphanus sativus were completely inhibited at the highest concentration (100 mg/L) of aqueous extracts. Raphanus sativus was more sensitive (89.92% - 85.29%), while Triticum durum was more adopted (90.699% - 88.17%) to aqueous extracts. Extracts were more effective in reducing the early seedling growth than in suppressing the seed germination. The inhibitory effect of these extracts occurred much more on the root length. Considerable differences in total phenolic contents (860.20 µgEAG/gDW) and flavonoids (1989.52 µgEQ/gMS) were found. The Ziziphus spina-christi leaf extracts could justify the use of this specie as an herbicide and can give a great success in agriculture.