Gurskaya O. Allelopathic activity of species of the genus Pyrethrum Zinn

The thesis focuses on the allelopathic activity of ekzometabolites of vegetative and generative organs, vegetable remains and rhizosphere soil of species P. parthenium (L.) Smith (varieties - White Gem, Phlora Pleno, Golden Ball, Snowball) and P. сoccineum (Willd.) Worosch. The research defines the contribution of some groups of biologically active compounds in the formation of allelopathic effects and aftereffects of plant exudations and identifies the elemental composition of leaves and inflorescences of P. parthenium and P. сoccineum. The allelopathic activity of ekzometabolites of P. parthenium and P. сoccineum during vegetative period has been evaluated for the first time. It has been shown that the plants of the genus P. parthenium accumulate more phytoinhibitors in comparison with P. сoccineum. Water-soluble extracts of Phlora Pleno and Snowball, ethanol-soluble extracts of Whitе Gem, Golden Ball and Phlora Pleno, volatile compounds of Snowball and Whitе Gem reveal the highest allelopathic activity among the varieties of P. parthenium. It has been established that the allelopathic activity of species of the genus Pyrethrum is determined by the qualitative and quantitative contents of biologically active compounds, in particular terpenoids, phenolic compounds, vitamins and organic acids and depends on the number of macro- and micronutrients in leaves and inflorescences of plants. The component composition of essential oils of leaves, inflorescences and seeds of P. parthenium and P. сoccineum, that were introduced on the territory of Ukraine, has been established for the first time. The highest maximum of accumulation of biologically active compounds falls on the beginning of vegetative period (vitamins), budding (flavonoides, tannins), flowering period (essential oils, the total amount of phenolic compounds, flavonoides), seeding period (organic acids). The high contents of phenolic compounds, bioflavonoids and organic acids have been found in the overground mass of vegetable remains as well.