Changes in essential oil content of dill (Anethum graveolens) organs under salinity stress

Salinity is one of the most serious environmental factors limiting crop production of marginal agricultural soils in many arid and semi-arid parts of the world. Effects of four levels of salinity (0, 4, 8 and 12 dS/m NaCl) on yield and essential oil content of dill (Anethum graveolens) organs (leaves, flowers and seeds) were investigated in 2010. A factorial experiment based on randomized complete block design with four replications was carried out at the Greenhouse of the University of Tabriz, Iran. Results indicated that mean leaf dry weight per plant under non-saline condition was considerably lower than that under saline conditions. However, the effect of salinity on dry weights of flowers and seeds was not significant. Mean essential oil yield was increased with increasing salinity. This improvement directly related with enhancing total yield under saline condition, since essential oil percentage was not significantly affected by salinity stress. The highest and the lowest percentage and yield of essential oil were obtained from seeds and leaves, respectively. Seeds and flowers were the most beneficial organs of dill for essence production. It was concluded that the dill plant is highly salt tolerant and it can well perform under NaCl salinities up to 12 dS/m.   Key words: Dill, essential oil, organs, salinity stress, yield.