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

Abstract

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