Evaluation of cycosel and salicylic acid on growth characteristics, physiologic and essence yield in lemon balm (Melissa officinalis L) under water stress

In order to investigate the effects of salicylic acid and cycocel under drought stress conditions on agronomic and biochemical properties and essential oil of lemon balm, an experiment as a factorial split-plot in a randomized complete block design with three replications was carried out in northwest of Yasuj province during 2019 and 2020. Drought stress as the main factor included 35% (control), 70% and 90% field capacity, and the subplots included cycocel (0 and 1000 μM) and salicylic acid (0 and 1 μM). Results showed that foliar application of salicylic acid and cycocel had significant effect on grain yield, essential oil percentage, plant height, fresh and dry weight of shoot and fresh and dry weight of root and the amount of catalase, peroxidase and malondialdehyde enzymes. The highest yield belonged to irrigation treatment after application of 35% moisture along with foliar application with cyclocel and salicylic acid. Also, the most of essential oil yield belonged to irrigation treatment after consuming 70% moisture along with foliar application with cyclocel and salicylic acid. In general, the results showed that foliar application of salicylic acid and cyclocel caused drought resistance in lemon balm, and therefore it is recommended for areas similar to the climatic conditions of the study.