Influence of Exogenous Salicylic Acid on the Germination of Ryegrass(Lolium perenne)Seeds under Low Temperature Stress

[Objective] To study the suitable concentration of exogenous salicylic acid(SA) for improving the ability of ryegrass seed germination under low temperatures.[Method] Ryegrass seeds were soaked with different concentrations of SA at 0,0.5,1.0,1.5,2.0 and 2.5 mmol/L for germination at 17 ℃ and seeds germination conditions were observed.[Result] Seeds germination ability increased with the increasing of exogenous concentrations of SA during 0-1.5 mmol/L,but it was prohibited with further increase of SA concentrations.The germination percentage,germination and germination index peaked at 1.5 mmol/L of SA and significantly higher than those at other concentrations of SA.[Conclusion] Under low temperature stress,1.5 mmol/L of exogenous SA was the most suitable concentration for improving the germination ability of ryegrass seeds.