Allelopathic Effect of Scentless Mayweed Extracts on Carrot

The aim of the study was to examine allelopathic effect of water extracts prepared from fresh biomass of scentless mayweed [Tripleurospermum inodorum (L.) C.H. Schultz] on germination and initial growth of carrot. The experiments were conducted to evaluate: i) the effect of extracts from different plant parts (root, stem, leaf and aboveground biomass) in 1, 5 and 10% concentration in Petri dishes, and ii) the effect of extracts from aboveground biomass in aforementioned concentrations in pots with soil. In Petri dishes, reduction of germination compared to the control was not significant and ranged from 0.5 to 11.1%. Extracts had more pronounced effect on growth and fresh weight of carrot seedlings. Root length was inhibited in all treatments and varied greatly depending on concentration and plant part, while shoot length was both promoted and stimulated. Fresh weight of seedlings was reduced in all treatments and amounted up to 30.5%. Plant parts differed in their allelopathic potential, and root extract exhibited the highest inhibitory effect. In experiment with soil, extracts from fresh mayweed biomass reduced germination for up to 16.1%. Extracts had no significant effect on fresh weight of carrot seedlings, while length of root and shoot were both stimulated and inhibited.