Investigation of Essential Oil and Citral Content, and Morpho-physiological Changes of Lippia citriodora in Response to Induction of Bioactive Compounds and Plant Growth Regulators

Background: Lippia citriodora H.B.K is an important medicinal and aromatic plant from the Verbenaceae family. Objective: The aim of this study was to investigation of essential oil percentage, E-citral (geranial) content and morphophysiological changes of Lippia citriodora in response to induction of bioactive compounds and plant growth regulators. Methods: This study has been conducted on the base of factorial experiment in randomized complete block design (RCBD) with 3 replications. The first factor included the application of bioregulators at four levels that were distilled water, 50 ppm gibberellic acid (GA3) + 50 ppm IBA, 50 ppm GA3 + 100 ppm IBA and 100 ppm GA3 + 50 ppm IBA. The second factor was chitosan inductions at two levels: distilled water and 400 ppm chitosan. The third factor was methanol induction at two levels: distilled water and 5% v/v methanol. Results: The measured traits were significantly affected (P≤0.01) by the interaction of bioregulators, methanol and chitosan except for plant height, number of branches, leave length that were significantly affected at 0.05 level. The highest content of essential oil achieved by 400 ppm chitosan and 5% V/V methanol. The highest amount of leaves number and E-citral content were observed at 400 ppm chitosan. The maximum value of root and stem fresh and dry weight and leaf dry weight were obtained at 50 ppm GA3 + 100 ppm IBA. Conclusion: Generally, the interaction of foliar application of plant growth regulators, methanol and chitosan could be positively effect on essential oil, E-citral (geranial) content and morpho-physiological traits