Allelopathic influence of common buckwheat root residues on selected weed species

This study was conducted to determine if common buckwheat (Fagopyrum esculentum Moench) root residues (BRR) in soil are effective in limiting the growth and metabolic responses of barnyard grass (Echinochloa crus-galli (L.) P. Beauv.), wind grass (Apera spica-venti L.), cleavers (Galium aparine L.), and tiny vetch (Vicia hirsuta L.). After removal of above ground parts, BRR of 14-day-old buckwheat plants remained in soil for an additional 7days when the weeds were seeded. After 30days of growth, biomass of above ground parts of the weeds as well as free and bound phenolic acids and flavonoids were determined. Antioxidant capacity and peroxidase activity were measured in barnyard grass and cleavers. The biomass of 30-day-old plants of barnyard grass and cleavers grown in bare soil was approximately 5- and 3.5-fold higher, respectively, than in plants grown in the presence of BRR. BRR did not affect the biomass of wind grass and tiny vetch plants, but activate the antioxidant response, increase in peroxidase activity, and the content of phenolic compounds in weed tissues, which indicates an adaptation to the stressful environmental conditions.