Chemical Composition and Phytotoxic Activity of Seriphidium terrae‐albae ( Krasch .) Poljakov (Compositae) Essential Oil

Abstract To evaluate the potential value of Seriphidium terrae‐albae ( Krasch .) Poljakov essential oil as bioherbicide, its chemical composition as well as phytotoxic activity was investigated. Seventeen compounds were identified via GC/MS, representing 98.1 % of the total oil, and the most abundant constituents were α‐thujone (43.18 %), β‐thujone (16.92 %), eucalyptol (17.55 %), and camphor (13.88 %). Phytotoxic assay revealed that the essential oil as well as its major constituents exhibited inhibitory activity on root and shoot growth of receiver plants in a dose‐dependent manner. When the concentration reached 20 μg/mL, root length of Amaranthus retroflexus was reduced to 31.3 %, 70.6 %, 36.9 %, and 66.6 % of the control, respectively, when treated with α‐thujone, eucalyptol, camphor, and the mixture of these compounds; meanwhile, root length of Poa annua was 3.0 %, 24.2 %, 0 %, and 4.4 % of the control when the same chemicals were applied. On the other hand, the essential oil showed a much stronger activity. At 1.5 μL/mL, root and shoot length of A. retroflexus and P. annua were reduced to 0.65 %, 0.5 %, and 1.53 %, 1.51 % of the control, respectively, and seed germination of A. retroflexus and P. annua was completely inhibited when the oil concentration reached 3 μg/mL and 5 μg/mL, respectively. This is the first report on the chemical composition of the essential oil of S. terrae‐albae , and our results indicated that it has the potential to be further exploited as a bioherbicide.