Allelopathic potential of segetal and ruderal invasive alien plants

TLDR: Tree of heaven is species with the strongest allelopathic potential and applying allelopathy in agriculture can reduce the use of synthetic pesticides.

Abstract: At the global level, the invasion of alien organisms is considered the second largest threat to biodiversity. The assumption is that the high allelopathic potential is one of the features that helps invasive plant species to spread to new areas. In the study was determined allelopathic potential of eight invasive plant species (donor species) and their impact on test-species. Donor species were Abutilon theophrasti Med. - velvetleaf (Malvaceae), Ambrosia artemisiifolia L. - ragweed (Asteraceae), Datura stramonium L. - white jimsonweed (Solanaceae), Xanthium strumarium L. - cocklebur (Asteraceae), Ailanthus altissima (Mill.) Swingle - tree of heaven (Simaroubaceae), Amorpha fruticosa L. - indigo bush (Fabaceae), Reynoutria japonica Houtte. - Japanese knotweed (Polygonaceae), Solidago gigantea Aiton - giant goldenrod (Asteraceae). Three cultivated plant species from three different plant families were used as test-species: Avena sativa L. - oats (Poaceae), Brassica napus L. - oilseed rape (Brassicaceae) and Helianthus annuus L. - sunflower (Asteraceae). Water extracts made of whole plants of donor species were applied to the seeds of the test-species. High allelopathic potential was proven for all species included in experiment. Allelopathic effects were exclusively negative. Impact on the germination for all species is much smaller in relation to the impact on the radicle and shoot length of the test-species. Perennial species had a stronger allelopathic potential than annual species. Tree of heaven is species with the strongest allelopathic potential. Its extracts inhibited germination, radicle and shoot length of oilseed rape 19%, 94.88% and 98.91% respectively. Applying allelopathy in agriculture can reduce the use of synthetic pesticides.