White and dark seeds of chicory were germinated in NaCl or KCl at 0, 30, 100 and 250 mmol L-1 for 7 days. The threshold salinity for germination capacity was 100 mmol L-1, beyond which NaCl exerted more toxic effect than KCl and white seeds had higher critical salinity (220 mmol L-1 NaCl and > 250 mmol L-1 KCl) than dark seeds (185 mmol L-1 NaCl and 200 mmol L-1 KCl). Germination speed was more salt-sensitive than germination capacity. High salinity delayed both onset and termination of germination. Embryo extension, particularly plumule growth, was more salt-sensitive than seed germination, with lower threshold salinity and complete cessation at high salinity. Upon release of salt stress, seeds readily recovered without lag; and recovery was better in dark seeds than in white seeds, from NaCl than from KCl and from high salt solutions than from low salt solutions. The depression of germination by high salt solutions of NaCl and KCl suggests an osmotic effect while the greater toxicity of NaCl than that of KCl suggests a specific ion effect. The osmotic effect dominates at high salinity with comparable effects of NaCl and KCl and maintenance of seed viability while the specific ion effect emerges at moderate salt levels with reduced seed viability and more toxicity of NaCl than of KCl. High salinity thus can be manipulated as a priming treatment, focusing germination in short time period with high speed.

Keywords: chicory, NaCl, KCl, germination, dimorphism.