EN
Lemon verbena (Lippia citriodora H.B.K.) from Verbenaceae family is a valuable aromatic and medicinal plant due to the extensive use of its essential oil in various pharmaceuticals and food products. However, the plant growth is highly sensitive to cold stress which could influence the quantity and quality of the extracted essential oil. The objective of this work was to investigate the interaction effect of anti-chilling agent and temperature on quality and quantity of essential oil produced from lemon verbena. The anti-chilling agents consisted of glycerol (GLY), ethylene glycol (EG), and polyvinyl alcohol (PVA) which was used separately or in combination with formulations at a total concentration of 6% v/v. After spraying the anti-chilling agents, the plants were maintained at a constant temperature in the range of 5–25 °C for 48 h. The results showed that the anti-chilling application had a bio-protective effect on the essential oil content and its components especially neral and geranial as oxygenated monoterpenes. The treatment with the best protective effect on essential oil content and its constituents was 6% v/v GLY at both low and high temperatures. Furthermore, the anti-chilling application especially the treatment of 6% v/v GLY and 3% v/v GLY + 3% v/v PVA had the positive effect on enzymes activities at critical temperatures of 5 °C. The foliar application of anti-chilling formulations could improve the quality and quantity of lemon verbena essential oil and enzymatic activities under low-temperature condition.