Effect of Water Stress on Morphological Traits, Essential Oil Content and Yield of Anise Hyssop (Agastache foeniculum [Pursh] Kuntze)

Anise hyssop is a prennial herb belonging to the Lamiaceae family. Essential oil of this plant is used in food, pharmaceuticals, cosmetics industries as well as flavoring liqueurs. Since water stress affects the growth, productivity, as well influences the active principles governing medicinal plants, in this research the effect of different water deficit stresses on such morphological traits as plant height, length and number of axillary shoots, stem diameter, leaf number, leaf area, fresh vs. dry weight of leaf, stem and roots, ratio of dry weight of roots to shoots, plant yield and essential oil content as well as yield was evaluated under a Randomized Completely Block Design (RCBD) with three replications. The 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 period), 100-70% of FC (100% at vegetative and 70% at reproductive stage), 85-100 % of FC (85% at vegetative and 100% at reproductive phase). All the mentioned traits, except the essential oil content, showed their highest and lowest degrees at 85-100% vs. 55% FC, respectively. In contrast, the highest amount of essential oil content was observed at 55% FC and the lowest one at 100-70%.