Allelopathic effects of ragweed compound thiarubrine-A on Brazilian pepper

The Brazilian pepper an exotic invasive plant species is quickly driving out native plants and decreasing the biodiversity in the Florida's Everglades National Park. It has infested more than 6,000 acres land in the Hole-in-the-Donut area (HID), where a restoration project was started to clear the pepper trees and the associated surface soil. Following the creation of compact elevated piles of surface soil and pepper tree mulch at the HID site, Brazilian pepper failed to establish on a number of piles. The persistence of common ragweed (Ambrosia artemisiifolia) on those soil piles, was proposed as a primary reason for the absence of Brazilian pepper. It was hypothesized that thiarubrine-A, a biologically active compound found in the roots of common ragweed, may be involved in the suppression of Brazilian pepper. This research study aimed to investigate the potential allelopathic effects of thiarubrine-A on seed germination, seedling growth and on root and shoot tissue of Brazilian pepper. A single application of thiarubrine-A delayed the Brazilian pepper seed germination and its direct application on the root, cotyledons and leaf tissues caused dark coloured lesions.