Asclepias syriaca was introduced in Romania as ornamental plant in XIX century. In present, this species can be encountered in various habitats such as meadows, forest edge, lakes shore, irrigation canals, edge of roads, various crops and orchards, tending to establish itself in agricultural crops. Asclepias syriaca owns a set of characteristics (high multiplication capacity, spreading capacity, resistance to abiotic stress factors, contains allelopathic substances) from which its competitiveness results. Its presence, more frequently, in anthropic ecosystems, including sunflower ecosystem create the basis for establishing the purpose of this study. The trials placed under laboratory conditions followed the interaction between Asclepias syriaca extracts based on leaves, stems and roots and germination, growth and early development of Helianthus annuus plants. The solvent used for extracts preparation was distilled water. As treatments we included â 9 extracts: roots (10%, 20%, 30%), steams (10%, 20%, 30%) and leaves (10%, 20%, 30%). The data obtained reveled that Asclepias syriaca extracts had an inhibitory effect on germination, growth and Helianthus annuus development. Extract based on rots of Asclepias syriaca reduced at highest the plants height, of fresh biomass and on sunflower seed germination. The seed germination (mean of nine variants) treated with extracts of Asclepias syriaca being 50% compared with control variant (86,67%). When treated with leaf aqueous extracts the sunflower plants exhibited the shortest height (2.08 – 3.65 cm), with significant differences compared to the control (7.24 cm). the plants in variants treaded with extract at 30% were the most affected, physiological processes being significant affected. The statistical data recorded enforce the understanding of yield loses from Asclepias syriaca infested crops.

Asclapias syriaca, Helianthus annuuss, germation, biomass, plant height

agronomy

Presentation: poster