Assessment of salt stress resistance of three Eucalypt species in first growth stages

Salinity is one of the most important abiotic stresses that according to its negative effects on plant growth، reduces lands’ potential productivity. Seed germination is the first stage of plant development، in which plant encounters salinity of soil. Thus، study of plant response to salinity in this stage can have an important role in determination of plant salinity resistance. The salinity resistance of plant can be determined in short time. In this study، in order to identify salinity resistance of three Eucalyptus species (E. microtheca، E. camaldulensis، E. saligna) in germination and initial growth stages، using MS media culture in vitro condition and using completely randomized factorial experiment with3 replications their seeds were exposed to 6 salinity treatments، including 0، 50، 100، 150، 200 and 250 Mm NaCl in laboratory condition. Germination percent، germination speed، seed vigor، root and shoot length، root and shoot fresh weight، root and shoot dry mass and total biomass were measured and used as salinity tolerance index (STI). E. microtheca was more salinity tolerant than E. camaldulensis and E. saligna. In order to achieve more confident results seeds of these 3 species were planted in different salinity classes of natural soil. After comparison، it was determined that results were quite consistent.