The effects of water extracts of Xeranthemum cylindraceum Sibth. et Sm. on seed germination of three weed species

Abstract

The present study focused on inhibitory effects of water extracts of flowers, leaves, stems and roots of Xeranthemum cylindraceum Sibth. et Sm. on the total germination percentage, germination rate and germination rate index of chickweed (Stellaria media [L.] Vill.), common ragweed (Ambrosia artemisiifolia L.) and velvetleaf (Abutilon theophrasti Medik.). Water extracts were made by soaking 10 g of plant biomass in 100 ml of distilled water on a shaker for 24 h. Batches of 50 (A. artemisifolia and S. media) or 30 (A. theophrasti) seeds were germinated in 0%, 10%, 20% and 50% extract solutions in three replicates. The extract of X. cylindraceum flower did not affect the germination percentage of test species but it did affect the germination rate and germination rate index of all three species. The highest concentration of leaf extract significantly reduced chickweed germination percentage, while it had no corresponding inhibitory activity on the other two species. Its 10% concentration even stimulated the germination of A. theophrasti seeds. Leaf extracts had inhibitory effects on the germination rate and germination rate index of all three species. Stem extract of X. cylindraceum had no effect on any germination parameter of common ragweed seeds. However, it had inhibitory effect on the germination rate and germination rate index of chickweed, and on germination rate of velvetleaf. Root extract acted inhibitory on all three germination parameters of chickweed seeds, and on the germination rate of velvetleaf. It had no inhibitory activity on the seeds of common rageweed. Based on available literature, the present study is the first to show that Xeranthemum cylindraceum has allelopathic properties.