Effects of salicylic acid on seed germination and seedling physiological characteristics of Zinnia elegans under salt stress

Zinnia elegans seed(cultivarFangfei No.1)was treated with 100 mmol/L NaCl.The effects of different concentration of exogenous salicylic acid(SA:0,0.5,1.0,1.5,and 2.0mmol/L)on salt stress-injuries were investigated during seed germination and seedling growth.The results indicated that SA can effectively alleviate the injuries of salt stress on seed germination and seedling growth of Z.elegans.Salicylic acid increased germination vigour,germination percentage,germination index,and subsequently increased plant height,stem diameter,root∶shoot ratio,chlorophyll content,proline,soluble sugar and soluble protein content and superoxide dismutase(SOD)and peroxide(POD)activity under salt stress.However,malondialdehyde(MDA)content(indicator of oxidative stress)was decreased by salicylic acid.Salicylic acid concentration of 1.0mmol/L produced the best effects whereas no mitigation effects were observed on seed germination or seedling growth under salt stress at 2.0mmol/L salicylic acid.It is suggested that salicylic acid concentrations of 0.5-1.5mmol/L could be used to alleviate salt stress-induced injuries.