Document Type: Research Paper
Department of Plant Eco-physiology, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.
Department of Horticulture, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
This research was carried out in 2014 and 2015 to assess the effects of salicylic acid (SA)
(0 and 1 mM) and abscisic acid (ABA) (0 and 50 µM) on essential oil content and yield of
ajowan (Carum copticum L.) organs under different irrigation intervals (I1, I2, I3, I4: irrigation
after 70, 100, 130 and 160 mm evaporation, respectively). Plants were sprayed by SA and ABA
at vegetative and reproductive stages. In both years, the biomass of vegetative organs (leaves
and stem), flower production and seed yield per unit area of ajowan decreased with decreasing
water availability. All organs mass improved by application of ABA and particularly SA.
Essential oil percentage of all organs increased, but essence yield decreased as a result of water
limitation. Reduction in essential oil yield of ajowan organs due to water stress strongly related
with the reduction of individual organ mass under stress. Foliar spray of ABA and especially
SA improved the medicinal and commercial value of ajowan under different irrigation intervals
by enhancing plant organs biomass and accumulation of more essential oil.