The effects of drought stress on seed germination and some of morphological and physiological traits in Trachyspermum ammi

In order to assess the response of ajowan to drought stress that induced by PEG 6000 on germination and growth stages, two separate experiments that in each useed completely randomized design with three replications were done. In first experiment, the response of germination of ajowan seeds was investigated to different levels of drought stress include osmotic potential of zero (control), - 1.5, -2, -2.5 and -3bar that prepared by PEG6000. The second experiment was same first, but in this experiment, morphological and physiological characters of ajowan in different level of drought stress were evaluated. Results of Anova at our data showed that drought stress has significant effect (p≤0/01) on germination characters such as germination percentage, germination rate, height of plumule, length of radicle, dry weight of radicle and plumule. Mean comparison of treatments showed, with increase in drought stress, all the above characters have been reduced. Morphological traits such as leaf area, fresh and dry weight of shoot and root and shoot dry weight ratio to root decreased under drought stress.