Change in Physiological Characteristics, Amino Acids and Performance of Echinacea purpurea L. Under Brassinolide and Surfactant in Response to Drought Stress

Drought, one of the major ecological limiting factors, has a significant effect on the growth and secondary metabolic process of medicinal plants. Water stress reduces the size, density, leaf surface of the plant and reduces the biomass, and not only changes the plant structurally, but also leads to fluctuations in their secondary chemical compounds. The present study was carried out to investigate the effect of using brassinolides and surfactant on drought stress tolerance on Sarkhargol medicinal plant at Islamic Azad University of Mahabad during 2016 - 2017. The studied factors include dryness at three irrigation levels of 70, 120 and 170 mm, evaporation from class A pan as the main factor, surfactant consumption at two levels (0 and 0.5 liters per hectare) and 24-epibrassinolide at three levels (0, 0.01 and 0.1 μmol) were as secondary factors. According to the results of the present study, drought stress had a decisive role in reducing the properties of Sarhargol medicinal plant, as well as the main effects of brassinolide, surfactant solution and drought stress according to the content of soluble sugars, proline, glycine betaine, amino acids, lysine and methionine. They had Due to the limitation of water resources, irrigation after 120 mm, use of brassinolide and surfactant can have a positive role in removing the damages of drought stress. In addition, brassinolide and surfactant led to increased tolerance to drought stress in Sarhargol medicinal plant, which led to relative resistance to drought and stability of the yield of dry matter of the plant and its essential oil.