Bioherbicidal evaluation of Sorghum halepense (L.) rhizome extract and its bioactive components against selected weed species

Abstract

Nowadays, one of the priorities in agricultural production is the usage of natural bioherbicides for weed control, instead of commercial herbicides which have a strong negative effect on human health and the environment. Due to its widespread distribution and the economic losses it causes to the global economy, Sorghum halepense has been described as one of the world’s most invasive plant and a dangerous weed. We here examined the possibility to exploit the phytotoxic and bioherbicide potential of this species against other weed species: Amaranthus retroflexus, Chenopodium murale and Datura stramonium. The rhizome extracts of S. halepense (concentration of 0.01, 0.1, 1, 2, and 5 mg/ml) notably reduce the final seed germination of C. murale and D. stramonium, especially at the highest investigated concentration, while A. retroflexus seed germination was not affected. Early seedling growth of A. retroflexus was stimulated by the rhizome extract, while in C. murale and D. stramonium the values of growth parameters were reduced. As revealed by UHPLC/ DAD/qqqMS2 metabolic profiling of polyphenolics, major bioactive compounds in S. halepense rhizom extract were phenolic acids: p-hydroxybensoic acid (pHB A), chlorogenic acid (CHL A), and p-coumaric acid (pCUM A). Analysis of bioherbicide potential of these compounds, applied in a series of concentrations (0.005, 0.01, 0.1, 0.2, and 0.3 mg/ml), revealed that pHB A, CHL A, and pCUM A, are the main responsible for the overall effects of S. halepense rhizom on selected weeds. These results highlight Sorghum halepense (L.) rhizomes, and their main constituents, as potent bioherbicides.