Effects of Salinity and Drought Stresses on Seed Germination and Seedling Growth of Desert Wheatgrass Agropyron desertorum

Considering forage grass species, germination is one of the important stages concerning the growing stage that is often influenced by environmental stresses, particularly salinity and drought stresses. Thus, this study aims to assess the effects of salinity and drought stresses on germination characteristics and seedling growth of desert wheatgrass, Agropyron desertorum (Fisch. ex Link) Schult. in laboratory conditions. Two separate experiments were conducted using completely randomized design with four replicates. Six salinity treatments (control, 50, 100, 150, 200 and 300 mM NaCl) and six drought treatments (control, -0.2, -0.4, -0.6, -0.8 and -1 MPa polyethylene glycol) were utilized in four replicates. Germination percentage and rate were calculated while computing the germinated seeds every day. Growth parameters (rootlet, shoot and seedling length), allometric index and seed vigor have been accordingly given. For each experiment, one-way ANOVA was used to determine significant effects of treatments and mean comparison was done by the means of Duncan method using SPSS software. Results showed that salinity and drought stresses had the significant effects on germination and growth indices of Agropyron desertorum so that germination rate and percentage, root length, shoot length, seedling length and seed vigor indices were decreased by increasing the concentrations of salinity and drought treatments. Also, seed germination and growth were observed only until -0.4 MPa drought level so that germination at ?s = -0.6 MP was completely stopped.