Allelopathic effects of three invasive alien plants on oilseed rape
Allelopathic effects of Ailanthus altissima (Simaroubaceae: EPPO List of Invasive Alien Plants), Asclepias syriaca (Apocynaceae) and Heracleum sosnowskyi (Apiales: EPPO A2 List) were studied on oilseed rape under laboratory conditions in Hungary. All three species are invasive alien plants in Hungary. A. syriaca regularly causes damage on crop production in agricultural fields. A. altissima is frequently found on the margins of fields or along roadsides and has a strong allelopathic effect on the plants in its near vicinity. H. sosnowskyi can have human health impacts as it produces not only allelochemicals but contains furanocoumarins which can cause human phytophotodermatitis. During the experiments, the allelopathic effect of aqueous extracts prepared from shoots of the alien plants in three concentrations was evaluated on the germination and early growth of oilseed rape. Extracts of A. altissima decreased germination of oilseed rape by 20%. Furthermore, growth of shoots decreased continuously with concentration, and at the highest concentration oilseed rape was 20% lower compared to the control. A. syriaca shoot extracts hindered germination the most strongly, with almost a 50 % reduction at the highest concentration. All three concentrations reduced growth of oilseed rape seedlings. H. sosnowskyi inhibited germination of seeds, where the strongest concentration reduced germination by 25%. Again, the growth of shoots decreased continuously with concentration and at the highest concentration, oilseed rape growth was approximately 50% lower compared to the control. The results indicate that extracts from the shoots of the invasive plants reduced germination as well as shoot and root growth of oilseed rape. Therefore, all three species should be managed when populations encroach into agricultural land.
Sources
Nadasy E, Pasztor G, Takacs A, Kovacs A (2018) Allelophatic effect of Ailanthus altissima, Asclepias syriaca and Heracleum sosnowskyi on germination and early growth of oilseed rape. NeoBiota conference, Oral Presentation, (Dun Maoghaire, Dublin, IE, 2018-09-03/07).