Esmail Nabizadeh, Farid Yousefi and Farzad Gerami
In order to evaluation the effect of seed osmo-priming by polyethylene glycol (PEG 6000) on safflower (cv. Pdideh) seed germination and seedling growth, a laboratory experiment was carried out at the Agronomy Department of Agriculture Faculty of Shahid Chamran University, Ahvaz, Iran, during 2011. Seeds primed with four osmotic potential levels (i.e. distilled water; OP0, -2 MPa; OP-2, -4 MPa; OP-4 and -6 MPa; OP-6) for 12 (D12), 24 (D24) and 36 (D36) hours priming duration. Experiment was arranged factorial (4 × 3) in a completely randomized design with three replications. In this study, seed germination percentage, germination rate, plumule and radicle length, radicle to plumule ratio, seed vigor index as well as plumule and radicle weight were investigated. Our results showed that, all studied traits significantly affected by osmotic potential levels except germination percentage and plumule weight. Also, osmo-priming duration had significant effect on all germination and seedling growth characteristic except plumule weight. Plumule and radicle lengths, seed vigor index and radicle weight significantly affected by interaction of treatments. All studied traits decreased by decreasing of osmotic potential levels. Therefore, OP-6 and D36 had the most inhibitory effect on studied characteristics. In general, results of present study suggest that, osmotic potential increasing and reduction of priming duration could improve seed germination and seedling growth parameters of safflower.