Developmental traits in grassland and agricultural plants under the influence of ragweed

The problem of invasion and naturalization some of adventive species is very important in current moment. First of all, it concerns the species which influence to the human being. The Ambrosia artemisifolia L. is an one of example of these species. This species quickly finds the optimal conditions to grow, it's not only the strong allergen but it also decreases the quality of phytocoenosis. Allelopathic activity of ragweed respectively towards other species remains unclear. That makes it difficult to understand the ragweed phytocenotic compatibility with the both cultural and wild-growing plant species. In current work we make an attempt to assess the allelopathic effect of the quarantine species Ambrosia artemisifolia L. on the growth and development of the widely used in Ukrainian agriculture five perennial grasses, as well as on two species of wild meadow mixed grass plants. Significantly lower seed germination of the following species under the effect of the water-soluble allelopathic substances of ragweed has been demonstrated: Helianthus annuus L., Medicago sativa L., Trifolium pretense L., Prunella vulgaris L., and Plantago major L. At the same time Hordeum vulgare L. has shown significantly higher seed germination under the effect of ragweed. Less sensitivity of the seedling standing stock in comparison to the seedling length has been demonstrated for the study species under the effect of the allelopathic substances of ragweed. Phytocoenotic compatibility of the studied cultural and wild-growing plants with the ragweed allelopathic activity has been shown.