Chemical Composition and Inhibitory Effects of Essential Oils on Germination and Seedling Growth of Barnyard Grass, Echinochloa crusgalli L.

Abstract

Hydrodistilled essential oils from twenty plant species grown in Egypt were analyzed by gas chromatographymass spectrometry (GC-MS). The isolated oils were enriched with monoterpene hydrocarbons (i.e., limonene, sabinene, β-pinene, γ-terpinene, α-phellandrene, β-phellandrene, δ-3-carene, cis-Ocimene) and oxygenated monoterpenes (i.e., terpinen-4-ol, β-thujone, 4-terpineol, linalool, α-citral, β-citronellol, 1,8-cineole, camphor, pulegone, α-terpinolene) except the oil of Schinus terebinthifolius which was enriched with sesquiterpenes, and the oil of Vitex agnus-castus which contained similar amounts of monoterpenes and sesquiterpenes. The inhibitory effects of the essential oils on seed germination and seedling growth of barnyard grass, Echinochloa crusgalli were examined. The oil of Myrtus communis was the most potent seed germination inhibitor at the tested concentrations (625, 1250, 2500, and 5000 mg L −1 ), followed by the oils of Pelargonium graveolens, V. agnuscastus, Cupressus macrocarpa and S. terebinthifolius, while the oils of Citrus lemon, Artemisia judaica and Cupressus sempervirens were the less effective. Furthermore, the oils of M. communis, A. monosperma, V. agnus-castus and P. graveolens showed the highest inhibition of root and shoot growth. However, the inhibition of root growth by all essential oils was greater than that of shoot growth. These results suggest that the essential oils may serve as natural herbicidal products.