Changes in essential oil content and composition of Agastache foeniculum under water stress at second harvest

To study the effect of different levels of water stress on essential oil content and composition of Agastache foeniculum Kuntze at second harvest, a field experiment in randomized complete block design with three replications was conducted. Water stress treatments were: 100% of field capacity (FC), 85% of FC, 70% of FC, 55% of FC, 100–85% of FC (100% at vegetative and 85% at reproductive phases), 100–70% of FC (100% at vegetative and 70% at reproductive phases), 85–100% of FC (85% at vegetative and 100% at reproductive phases). The highest of essential oil content was observed at 70% of FC (1.69) and 100–85% of FC (1.67). Also the treatment 85% of FC (1.33) caused the lowest of essential oil content. There was not significant different between other treatments. The main essential oil constituent was methyl chavicol which showed a increasing with progress water stress till 70% of FC and then decreased at 55% of FC treatment. Limonene, another main component was decreased with increasing water stress levels from 100 of FC to 70% of FC. The highest amount of methyl chavicol (98.3%) and limonene (2.4%) were found at 70% of FC and 85–100% of FC, respectively.