Effects of Exogenous Salicylic Acid on Physiological Characteristics of Peanut Seedlings under Iron-Deficiency Stress

The effects of salicylic acid (SA) on iron (Fe) deficiency in peanut (Arachis hypogaea L.) were studied by adopting the hydroponic experiment. Iron deficiency caused serious chlorosis, inhibited plant growth and dramatically decreased the concentration of Fe in the roots. Furthermore, it decreased the active Fe content and chlorophyll content, and disturbed ionic homeostasis. In addition, Fe deficiency significantly increased the content of malondialdehyde (MDA) and the superoxide anion (O2•−) generation rate. Addition of SA increased Fe concentration in the shoots and roots, active Fe content, chlorophyll content, the net photosynthetic rate, and transpiration rate. Moreover, SA supplementation alleviated the excess absorption of manganese (Mn), copper (Cu) and zinc (Zn) induced by Fe deficiency. In addition, the chlorosis symptom was alleviated and the plant growth was improved. Meanwhile, addition of SA increased the activities of catalase (CAT) and peroxidase (POD), and decreased the content of MDA and the O2•− generation rate. These results suggest that exogenous SA can alleviate Fe-deficiency induced chlorosis by promoting the plant growth, improving the efficiency of Fe uptake, translocation and utilization, protecting antioxidant enzymes system, and stimulating mineral element maintenance.