Chemical characterization and allelopathic potential of volatile oil of Eucalyptus tereticornis against Amaranthus viridis

Abstract

The present study investigated the chemical composition and allelopathic potential of volatile oil from Eucalyptus tereticornis on growth and establishment of Amaranthus viridis, a wasteland weed. The volatile oil was rich in monoterpenoids and a total of 34 components were identified by gas chromatography/gas chromatography–mass spectroscopy analyses, constituting 98.52%. α-Pinene (32.5%) and 1,8-cineole (22.4%) were the two major constituents. The volatile oil and two major components were evaluated for their allelopathic potential against A. viridis. A significant reduction in early seedling growth and seedling vigor of A. viridis was observed in response to volatile oil or its major monoterpenes. Further, the contents of photosynthetic pigments, i.e. chlorophylls a and b, and carotenoids, and cellular respiration in oil-/monoterpene-treated seedlings were significantly reduced thereby indicating adverse effects of the oil on photosynthetic machinery and energy metabolism. Based on the study, it can be concluded volatile oil of E. tereticornis possess allelopathic potential and could be explored as bioherbicide for future weed management programs.