Na2SO4, NaCl and Polyethylene glyecl (PEG 6, 000 mol. wt. ) were used in a series of labbased experiments to comparatively investigate their effect on germination of Puccinellia tenuiflora and its mechanism. The results showed that total germination percentage linearly declined with decreasing osmotic potential (OP) in solutions of NaCl, Na2SO4 and PEG. On isopotential basis, the percent of germination in tested solutions was Na,SO4>NaCl>PEG. NaCl and Na2SO4 influence germination chiefly due to changing wat...