The allelochemical potential of an invasive ornamental plant, the Indian blanket flower (Gaillardia pulchella Foug.)

Abstract

Abstract Global spread of invasive plant species threatens biodiversity significantly, with a particularly high presence of invasives in the Asteraceae family. This is partly due to their wide use as ornamental plants and their rapid reproduction and allelopathy. The Indian blanket flower ( Gaillardia pulchella ) is a native North American species widely used as an ornamental plant and has become invasive in other countries. Although it contains bioactive compounds, its allelopathic impact on other plants has been largely unexplored. We conducted in vitro tests on oilseed rape ( Brassica napus ) germination and early growth to assess blanket flower's allelopathy. Seeds were exposed to aqueous extracts at three different concentrations (10%, 20%, and 40%). The 40% extract significantly inhibited germination during the treatment. All three concentrations inhibited root growth, with the 40% treatment showing this effect from the second day. In contrast, the extracts promoted significantly shoot elongation. Fresh weight of seedlings was not affected by the extract, but the 10% treatment resulted in higher mass. These findings provide evidence of blanket flower's allelopathic effects, shedding light on its invasive potential.