Phytotoxicity Study on Bidens sulphurea Sch. Bip. as a Preliminary Approach for Weed Control

Abstract

Farmers of the Franca region in Brazil observed that Bidens sulphurea was able to eliminate the Panicum maximum weed, which infected coffee plantations, without affecting the crop. In an effort to determine if the inhibitory effects observed were due to the presence of phytotoxic compounds from leaves and roots, a biodirected isolation and spectroscopic characterization has been carried out. The leaf dichloromethane and root acetone extracts were the most active, and the former appeared to be more phytotoxic to the target species, including four weeds. A total of 26 compounds were isolated from leaves and roots, and four of them are described here for the first time. The major compounds in the leaf extract are the sesquiterpene lactones costunolide, reynosin, and santamarine, and these showed marked inhibition. Amaranthus viridis and Panicum maximum were the most sensitive species of the weeds tested. These three phytotoxic lactones were also evaluated on A. viridis and P. maximum under hydroponic conditions. A. viridis was the most affected species with the three lactones, and santamarine was the most phytotoxic compound on both. This is the first time that the phytotoxicity of sesquiterpene lactones has been evaluated on hydroponic culture. The work described here is a preliminary approach for the use of B. sulphurea for weed control in agriculture, both as a cover crop and by use of its components as natural herbicide leads.

Recent advances in allelopathy for weed control: from knowledge to applications

“…Under hydroponic conditions, costunolide, reynosin and santamarine inhibited growth of Amaranthus viridis and Panicum maximum . These sesquiterpenes were isolated from Bidens sulphurea , which is used as a cover crop in Brazil …”

Phytotoxic Potential of Benzyl Salicylate and Benzyl Benzoate on Bioindicator and Invasive Species

“…Other authors used pure compounds extracted from different plant species and found their phytotoxic effects on the growth of T. aestivum coleoptiles (Anese, Jatobá, Grisi, Gualtieri, Santos, & Berlinck, 2015;Miranda et al, 2015;Jatobá et al, 2016;Silva et al, 2017). Thus, they confirmed that the initial growth bioassays of T. aestivum coleoptiles are a classic and efficient method to evaluate the phytotoxic activity of compounds belonging to the secondary plant metabolism (Hancock et al, 1964).…”

“…The authors used these bioindicator species and reported root and shoot inhibition mainly at the highest concentration tested. They also reported that there was a rapid decrease in inhibition when the compounds used were diluted, and in some cases, growth stimulus was observed (Miranda et al, 2015;Silva et al, 2017).…”

Bioassay-Guided Isolation and Structure Elucidation of Fungicidal and Herbicidal Compounds from Ambrosia salsola (Asteraceae)

“…Although, these two sesquiterpene lactones are structurally similar, the lack of a double bond in positions 1 and 2 in confertin and, in our opinion even more relevant, the five-membered lactone ring fused at positions 7 and 8 (rather than at positions 6 and 7) apparently contributed to the better phytotoxicity found in confertin than in neoambrosin. Sesquiterpene lactones have previously been reported to be phytotoxic [7,22,23,24].…”