Salicylic acid increases drought adaptability of young olive trees by changes on redox status and ionome

Different SA concentrations (10, 100 and 1000 mu M) were applied in young olive trees (Olea europaea L.) subjected to drought and rewatering. Plants treated with 10 mu M exhibited a close behavior to SA-starved plants. Although both 100 and 1000 mu M improved the balance between ROS production and scavenging, 100 mu M was more efficient. During drought, 100 mu M improved ROS detoxification and scavenging by the maintenance or overaccumulation of soluble proteins. During recovery, soluble proteins return to well-watered values and increased the investment in non-enzymatic antioxidants. 100 mu M was also the most effective in plant ionome regulation, improving macro and micronutrients uptake, namely P, Fe, Mn and Zn, and changing mineral allocation patterns. Therefore, 100 mu M also countered the drought-induced decline in total plant biomass accumulation. The application of suitable SA concentrations is an efficient tool to improve cellular homeostasis and growth of plants subjected to recurrent drought episodes.