Changes in essential oil content of Lippia citriodora in response to induction of bio-active compounds and plant growth regulators

Background & aim: Bioactive compounds and plant growth regulators could change a plant’s essential oil content and composition. In this study, the effect of bioactive compounds and plant growth regulators on lippia citriodora was investigated. Objective: This experiment was done with three replications on the basis of factorial experiment in randomized complete block design. The bio-regulators were sprayed in four levels, i.e. distilled water, 50 ppm gibberellic acid (GA3) + 50 ppm indole-3-butyric acid (IBA), 50 ppm GA3 + 100 ppm IBA, and 100 ppm GA3 + 50 ppm IBA. The chitosan was sprayed in two levels: distilled water and 400 ppm chitosan. The methanol was sprayed in two levels: distilled water and 5% v/v methanol. The essential oil was extracted by hydrodistillation method and analyzed by GC and GC/MS. Results: Thirty-two compounds were identified, representing 95.08% of the total essential oil. The main components were E-citral (geranial) (25.02%), Z-citral (neral) (16.04%), ar-curcumene (10.37%), caryophyllene oxide (9.56%), spathulenol (6.83%), limonene (4.99%) and (E)-caryophyllene (2.29%). The studied traits were significantly affected (p < 0.01) by the interaction of bioregulators, methanol and chitosan application. Conclusion: Foliar application of IBA, GA3, chitosan and methanol could increase aromatic values of L. citriodora essential oil.