study the effect of salinity levels and seed priming on germination and seedling properties of two medicinal plant species from asteraceae family

soil and water sources salinity are important constrains which threat the sustainable agriculture production in iran. in order to evaluate the effect of different antioxidants and salinity levels on germination and seedling properties of two medicinal species (cnicus benedictus l.), and (cichorium intybus l.), an experiment was conducted using a factorial based on completely randomized design with four replications at special crops laboratory of ferdowsi university of mashhad. the studied factor for each plant included: seed priming at 4 levels including control (distilled water), ascorbic acid (40 mm), gibberlic acid (75 mg.lit-1) and salicylic acid (1.5 mm), and five salinity levels according to electrical conductivity by adding nacl to distilled water (control, 5,10,15 and 20 ds.m-1). according to results, pretreatment with salicylic acid improved all of the germination and seedling properties in cnicus benedictus l. but gibberlic acid could to improved germination and seedling properties in cichorium intybus l. species. there were strong correlation between germination rate and radical and caulicle length especially on cichorium intybus species. generally, seed priming with gibberlic acid and salicylic acid could improve germination and seedling properties of these two species. both species showed a reliable tolerance to nacl salinity at germination stage, and germination was 60% compared with control at 20 ds.m-1 treatment.