Essential Oil of the Brazilian Native Species <i>Hesperozygis ringens</i>: A Potential Alternative to Control Weeds

Abstract

This study evaluated the allelopathic effect of the Hesperozygis ringens essential oil using dicotyledonous and monocotyledonous seeds which are classified as weeds [Bidens pilosa and Lolium multiflorum], bioindicators [Lactuca sativa and Avena strigosa] and crops [Glycine max and Oryza sativa]. The essential oil from the leaves was extracted and analyzed by gas chromatography coupled to mass spectrometry and gas chromatography with flame ionization detector. The extractive was diluted in ethanol, Tween 20 and water, and then tested at concentrations of 0.25, 0.50, 1.00, 2.50, and 5.00% (v/v). Water and the highest concentration of the solvents were used as control groups. The analyzed variables were germination, emergence velocity index, roots and shoot lengths and total seedlings length. Pulegone was the major essential oil compound representing 82.02% of the composition. Considering dicot seeds, the highest concentration of the extractive completely inhibited the germination of Bidens pilosa without affecting the germination of Lactuca sativa and Glycine max. On monocots, the highest essential oil concentration affected the germination of Lolium multiflorum and Avena strigosa without affecting the Oryza sativa one. The results indicate that the extractive has the potential to control weeds because they were more affected than the crops.