Effect of Humic Acid and Folic Acid on Seed Germination Properties of Echinacea Purpurea under Salt Stress Conditions

In order to investigate the effect of humic acid and folic acid on seed germination of Echinacea purpurea under natural salinity stress, a factorial experiment based on completely randomized design was conducted in three replications at Seed Technology Lab of Shahed University in 2017. The experiment factors consisted of humic acid at three levels (0, 200 and 400 mg/lit), folic acid at three levels (0, 200 and 400 mg/lit) and salinity stress at four levels (0, 4, 8 and 12 ds/m). The results showed that there were significant differences in humic acid, folic acid and salinity stress interaction on germination percentage, germination average, stem length, seedling fresh weight and seedling index. The highest germination percentage (100%) was observed in the combination of humic acid and folic acid at 200 mg.lit-1 and no salinity stress. Under stress conditions of 12 dS.m-1 , the amount of humic acid 200 mg.lit-1 and folic acid 400 mg.lit-1 improved germination to 75.55%. Maximum length and weight index of seedling straw was related to non-use of organic acids and lack of salt stress with a mean of 58.63 and the application of humic acid at 200 mg.lit-1 and folic acid at concentration of 400 mg.lit-1 in 12 ds.m-1 stress with an average of 0.68. Application of organic acids improved seed germination characteristics and growth indices of coneflower plant in salt stress conditions.